# SolidHaus — Addendum: Pre-printed Labels, Item Types, Consumables, Svelte, Multi-User

**Supersedes / amends:** PROJECT_SPECIFICATION.md, CLAUDE_CODE_GUIDE.md
**Date:** 2026-02-26 (v2)

---

## 1. Pre-Printed Label Sheets (Not On-Demand)

### The Concept

Instead of printing one label at a time when creating items, **pre-generate sheets of labels with unused IDs**. You peel off a label, stick it on an item, then scan it in the app to associate it with the item's data. This is similar to how asset tags work in enterprise IT.

### ID Format Change

**Old:** 6-character nanoid
**New:** 7-character nanoid from a 30-char alphabet (no ambiguous chars)

```typescript
import { customAlphabet } from 'nanoid';
const ALPHABET = '23456789abcdefghjkmnpqrstuvwxyz'; // lowercase, no 0/o/1/i/l
const generateId = customAlphabet(ALPHABET, 7);
// Examples: "za3rbam", "k7xhw2n", "p4fvt8c"
```

- 30^7 ≈ 21.8 billion combinations — effectively infinite for household use
- Lowercase is easier to type manually and reads better in URIs
- 7 chars gives more headroom for pre-generating batches without collision worry

### Label Sheet Generation

Generate a PDF of label sheets (A4 or letter), each cell containing:

```
┌────────────────┐
│ ▄▄▄▄▄  haus:// │
│ █    █ za3rbam │
│ █    █         │
│ ▀▀▀▀▀         │
└────────────────┘
```

For Brother P-touch tape, generate a continuous strip:

```
┌──────┬──────┬──────┬──────┬──────┬──────┐
│ QR   │ QR   │ QR   │ QR   │ QR   │ QR   │
│za3rb │k7xhw │p4fvt │m2bck │r9gnj │w5dtx │
└──────┴──────┴──────┴──────┴──────┴──────┘
```

### Pre-Generation Workflow

```
1. [App: Settings > Label Sheets]
2. [Generate 50 new IDs]  → creates 50 "unassigned" ID records in DB
3. [Download PDF / Print to P-touch]
4. [Physically apply labels to items around the house]
5. [Scan label with app → "New item with ID za3rbam" → Enter name/details]
```

The IDs exist in the database as "unassigned" entries until scanned and linked to an item. This means scanning an unknown-but-valid ID (one that matches the format) prompts: "This looks like a SolidHaus label. Create a new item?"

### Implementation

```typescript
interface PreGeneratedId {
  id: string;         // the 7-char nanoid
  generatedAt: string;
  assignedTo: string | null;  // null = unassigned, else item shortId
  batchId: string;    // which print batch this came from
}

// New IndexedDB store
preGeneratedIds: {
  key: string;
  value: PreGeneratedId;
  indexes: {
    'by-batch': string;
    'by-assigned': string;
  };
}
```

---

## 2. URI Scheme: `haus://`

### Format

```
haus://za3rbam
```

- **Protocol:** `haus://` — short, memorable, unique enough
- **Path:** the 7-character item ID
- **Full example in QR code:** `haus://za3rbam`

### How QR Scanning + Deep Linking Works

| Platform | Behavior when scanning `haus://za3rbam` |
|----------|----------------------------------------|
| **Android (Capacitor native app)** | Intent filter catches `haus://` scheme → opens app directly to item |
| **iOS (Capacitor native app)** | URL scheme registered in Info.plist → opens app directly to item |
| **Android (installed PWA via Chrome)** | PWA won't catch custom scheme. Needs workaround (see below). |
| **iOS (Safari PWA)** | Won't work. Custom schemes need native app. |
| **Any phone, no app installed** | Camera shows "haus://za3rbam" as text. User must manually open app. |

### The Deep Link Problem for PWAs

Custom URI schemes (`haus://`) **do not work with PWAs**. PWAs can only handle `https://` URLs on Android (via Web App Manifest scope + intent filters that Chrome creates when installing PWA).

**Dual-encoding solution**: Encode QR codes with an HTTPS URL that falls back gracefully:

```
https://haus.toph.so/za3rbam
```

This web address:
1. **If Capacitor native app is installed:** Android App Links / iOS Universal Links intercept → opens app
2. **If PWA is installed on Android:** Chrome's intent filter for the PWA scope intercepts → opens PWA
3. **If nothing installed:** Opens browser → landing page says "Install SolidHaus" with item preview

The QR code itself contains `https://haus.toph.so/za3rbam`. The app's ID parser extracts the 7-char ID from either format:

```typescript
export function parseItemId(rawValue: string): string | null {
  // Pattern 1: HTTPS URI — https://haus.toph.so/za3rbam
  const httpsMatch = rawValue.match(/haus\.toph\.so\/([23456789a-hjkmnp-z]{7})$/);
  if (httpsMatch) return httpsMatch[1];

  // Pattern 2: Custom scheme — haus://za3rbam
  const schemeMatch = rawValue.match(/^haus:\/\/([23456789a-hjkmnp-z]{7})$/);
  if (schemeMatch) return schemeMatch[1];

  // Pattern 3: Raw ID
  const rawMatch = rawValue.match(/^[23456789a-hjkmnp-z]{7}$/);
  if (rawMatch) return rawMatch[0];

  return null;
}
```

### Recommendation

**Use `https://haus.toph.so/{id}` as the canonical QR content.** Register `haus://` as a custom scheme in the Capacitor native app for bonus direct-launch capability. The HTTPS URL works everywhere and degrades gracefully.

---

## 3. Item Types & Lifecycle

### Type Taxonomy

```typescript
type ItemType =
  | 'durable'      // Long-lasting items (tools, furniture, electronics)
  | 'consumable'   // Items that get used up (batteries, tape, screws)
  | 'disposable'   // Single-use items (paper plates, trash bags)
  | 'perishable'   // Food/drink with expiry (pantry, fridge, freezer)
  | 'media'        // Books, DVDs, games
  | 'clothing'     // Wearable items
  | 'document'     // Important papers, manuals, certificates
  | 'container'    // Boxes, bins — items that hold other items
  ;
```

### RDF Mapping

```turtle
solidhaus:ItemType a rdfs:Class ;
    rdfs:label "Item Type"@en .

solidhaus:Durable a solidhaus:ItemType ;
    rdfs:label "Durable"@en ;
    rdfs:comment "Long-lasting items: tools, furniture, electronics, appliances."@en .

solidhaus:Consumable a solidhaus:ItemType ;
    rdfs:label "Consumable"@en ;
    rdfs:comment "Items that deplete with use: batteries, tape, screws, ink, cleaning supplies."@en .

solidhaus:Disposable a solidhaus:ItemType ;
    rdfs:label "Disposable"@en ;
    rdfs:comment "Single-use items: paper plates, trash bags, wipes."@en .

solidhaus:Perishable a solidhaus:ItemType ;
    rdfs:label "Perishable"@en ;
    rdfs:comment "Food and drink with expiration dates."@en .

solidhaus:itemType a rdf:Property ;
    rdfs:domain schema:IndividualProduct ;
    rdfs:range solidhaus:ItemType .
```

### Quantitative Properties (for Consumables & Perishables)

Items that get used up need quantity tracking:

```typescript
interface QuantityInfo {
  currentAmount: number | null;   // e.g., 750
  originalAmount: number | null;  // e.g., 1000
  unit: string;                   // e.g., "ml", "g", "pcs", "sheets", "%"
  lowThreshold: number | null;    // alert when below this (e.g., 100)
  expiryDate: string | null;      // ISO date, for perishables
}
```

RDF properties:

```turtle
solidhaus:currentQuantity a rdf:Property ;
    rdfs:label "Current Quantity"@en ;
    rdfs:comment "Current amount remaining. Pair with quantityUnit."@en ;
    rdfs:domain schema:IndividualProduct ;
    rdfs:range xsd:decimal .

solidhaus:originalQuantity a rdf:Property ;
    rdfs:label "Original Quantity"@en ;
    rdfs:comment "Amount when full/new."@en ;
    rdfs:domain schema:IndividualProduct ;
    rdfs:range xsd:decimal .

solidhaus:quantityUnit a rdf:Property ;
    rdfs:label "Quantity Unit"@en ;
    rdfs:comment "Unit of measurement: ml, l, g, kg, pcs, sheets, %."@en ;
    rdfs:domain schema:IndividualProduct ;
    rdfs:range xsd:string .

solidhaus:lowThreshold a rdf:Property ;
    rdfs:label "Low Threshold"@en ;
    rdfs:comment "Alert when currentQuantity drops below this value."@en ;
    rdfs:domain schema:IndividualProduct ;
    rdfs:range xsd:decimal .
```

schema.org already has `schema:weight` and `schema:size`, but for dynamic tracking of "how much is left" we need the custom properties above.

### Pantry / Kitchen Extension

With perishable items, this naturally extends to pantry management:

```turtle
<items/olive_oil_01>
    a schema:IndividualProduct ;
    schema:name "Olivenöl — Bertolli Extra Vergine" ;
    solidhaus:itemType solidhaus:Consumable ;
    solidhaus:currentQuantity 400 ;
    solidhaus:originalQuantity 1000 ;
    solidhaus:quantityUnit "ml" ;
    solidhaus:lowThreshold 100 ;
    solidhaus:custodyState solidhaus:CheckedIn ;
    solidhaus:supposedToBeAt <locations/kueche-regal> ;
    solidhaus:storageTier solidhaus:HotStorage .

<items/flour_01>
    a schema:IndividualProduct ;
    schema:name "Mehl Type 405" ;
    solidhaus:itemType solidhaus:Perishable ;
    solidhaus:currentQuantity 800 ;
    solidhaus:originalQuantity 1000 ;
    solidhaus:quantityUnit "g" ;
    solidhaus:lowThreshold 200 ;
    schema:expires "2026-09-15"^^xsd:date ;
    solidhaus:supposedToBeAt <locations/kueche-schrank> .
```

### Quick-Update UX for Consumables

When scanning a consumable, offer a fast "update quantity" flow:

```
[Scan olive oil bottle]
  → [Card shows: "Olivenöl Bertolli — 400ml / 1000ml (40%)"]
  → [Quick actions: "Almost empty" | "Half left" | "Just opened" | "Custom"]
  → [Tap "Almost empty" → sets to ~100ml]
  → [If below threshold → "Add to shopping list?" prompt]
```

---

## 4. Barcode Format Support

### What Formats Can Be Read?

| Format | Barcode Detection API (Chrome) | ZXing (fallback) | Capacitor ML Kit | Notes |
|--------|-------------------------------|-------------------|-----------------|-------|
| **QR Code** | ✅ | ✅ | ✅ | Our primary format |
| **DataMatrix** | ✅ | ✅ | ✅ | Very compact, great for small labels |
| **Code 128** | ✅ | ✅ | ✅ | Linear, good for tape labels |
| **EAN-13/UPC** | ✅ | ✅ | ✅ | Product barcodes (scan existing products) |
| **Aztec** | ✅ | ✅ | ✅ | |
| **PDF417** | ✅ | ✅ | ✅ | |

**All common formats are supported across all platforms.** QR is the best default because:
- Highest information density for small size
- Error correction built in
- Phone cameras auto-recognize and offer to open URLs
- Works well even when slightly damaged or at angle

DataMatrix is a great alternative for very small labels (it's more compact than QR at small sizes).

### Scanning Existing Product Barcodes

The app should also recognize standard EAN/UPC barcodes on commercial products. When scanning a product barcode (e.g., the EAN-13 on a bottle of olive oil):
1. Look up in local database first (maybe you've already cataloged it)
2. If not found, optionally query an open product database (Open Food Facts, etc.)
3. Offer to create a new item pre-filled with product info

This is a nice-to-have for Phase 2+.

---

## 5. Framework: SvelteKit + Capacitor (Not React)

### Why Svelte/SvelteKit Over React

Given the preference for Svelte, the recommended stack is:

| Layer | Technology |
|-------|-----------|
| **Framework** | SvelteKit 2 (Svelte 5 with runes) |
| **Build** | Vite (built into SvelteKit) |
| **Native wrapper** | Capacitor (Android + iOS) |
| **Desktop** | Tauri 2 (optional, later) |
| **Styling** | Tailwind CSS 4 |
| **State** | Svelte 5 runes ($state, $derived, $effect) — no external state library needed |
| **Routing** | SvelteKit file-based routing |
| **Barcode (native)** | @capacitor/barcode-scanner or @capacitor-mlkit/barcode-scanning |
| **Barcode (web)** | Barcode Detection API + ZXing fallback |
| **Local DB** | IndexedDB via idb (same as before) |
| **CRDT** | Automerge (for multi-user, see §6) |

### SvelteKit + Capacitor Setup

This is a well-documented, production-proven path:

```bash
# Create SvelteKit project
npx sv create solidhaus
cd solidhaus

# Add static adapter (required for Capacitor)
npm install -D @sveltejs/adapter-static

# Add Capacitor
npm install @capacitor/core @capacitor/cli
npx cap init solidhaus so.toph.solidhaus --web-dir build

# Add platforms
npm install @capacitor/android @capacitor/ios
npx cap add android
npx cap add ios

# Add barcode scanner
npm install @capacitor/barcode-scanner
# or for ML Kit (more powerful):
npm install @capacitor-mlkit/barcode-scanning

# Other deps
npm install nanoid idb bwip-js date-fns
npm install -D tailwindcss @tailwindcss/vite
```

**svelte.config.js:**
```javascript
import adapter from '@sveltejs/adapter-static';
import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';

export default {
  preprocess: vitePreprocess(),
  kit: {
    adapter: adapter({
      fallback: 'index.html'  // SPA mode for Capacitor
    })
  }
};
```

**src/routes/+layout.ts:**
```typescript
export const ssr = false;       // Capacitor needs client-side only
export const prerender = false;
```

### Deep Linking with Capacitor

Register the custom URI scheme and HTTPS App Links:

**capacitor.config.ts:**
```typescript
const config: CapacitorConfig = {
  appId: 'so.toph.solidhaus',
  appName: 'SolidHaus',
  webDir: 'build',
  server: {
    // For deep linking via HTTPS
    androidScheme: 'https'
  },
  plugins: {
    // App Links / Universal Links configuration
  }
};
```

**AndroidManifest.xml additions:**
```xml
<!-- Custom scheme: haus:// -->
<intent-filter>
  <action android:name="android.intent.action.VIEW" />
  <category android:name="android.intent.category.DEFAULT" />
  <category android:name="android.intent.category.BROWSABLE" />
  <data android:scheme="haus" />
</intent-filter>

<!-- HTTPS App Links: https://haus.toph.so/* -->
<intent-filter android:autoVerify="true">
  <action android:name="android.intent.action.VIEW" />
  <category android:name="android.intent.category.DEFAULT" />
  <category android:name="android.intent.category.BROWSABLE" />
  <data android:scheme="https" android:host="haus.toph.so" />
</intent-filter>
```

### Is There a "Svelte Native"?

**Short answer: not really, not in a usable way.**

- **NativeScript + Svelte** existed but is stuck on Svelte 4 and not actively maintained for Svelte 5.
- **Lynx** (ByteDance) has an agnostic core but only works with React currently. Svelte support requires a custom renderer API that's being worked on by the Mainmatter team but isn't ready.
- **Capacitor** is the pragmatic choice — it wraps your web app in a native WebView with full access to native APIs (camera, Bluetooth, file system, deep links). It's not "truly native" rendering, but for an inventory app the performance difference is negligible.
- **Tauri 2** supports Android and iOS and could be an alternative to Capacitor, with Rust backend instead of Java/Swift. More bleeding-edge but the SvelteKit integration is officially documented.

**Recommendation: SvelteKit + Capacitor.** It's the most mature path for Svelte on mobile with native features (barcode scanning, deep links, Bluetooth).

---

## 6. Multi-User & Offline-First (Hard Requirement)

### The Scenario

Multiple household members scan/update items independently:
- Person A scans the drill in the workshop (phone offline in basement)
- Person B logs the drill as lent to neighbor (phone online upstairs)
- Both changes eventually sync and resolve

### Architecture: CRDT + Solid Pod

With multi-user as a hard requirement, simple LWW is no longer sufficient. We need CRDTs.

**Recommended approach: Automerge as the sync layer, Solid Pod as the persistence/sharing layer.**

```
Device A (Phone)         Device B (Tablet)
     │                        │
     ▼                        ▼
┌─────────────┐        ┌─────────────┐
│ Local        │        │ Local        │
│ Automerge    │        │ Automerge    │
│ Document     │        │ Document     │
│ (IndexedDB)  │        │ (IndexedDB)  │
└──────┬──────┘        └──────┬──────┘
       │                       │
       ▼                       ▼
   ┌──────────────────────────────┐
   │      Sync Server             │
   │  (automerge-repo-server      │
   │   on NixOS infrastructure)   │
   └──────────────┬───────────────┘
                  │
                  ▼
            ┌───────────┐
            │ Solid Pod  │
            │ (RDF export│
            │  periodic) │
            └───────────┘
```

### How It Works

1. **Each device** maintains a local Automerge document with all inventory data
2. **Automerge-repo** handles sync between devices via a WebSocket relay server
3. **Offline**: Changes accumulate locally in the Automerge doc. When back online, automerge-repo syncs automatically — merges are conflict-free by design
4. **Solid Pod integration**: A periodic job serializes the Automerge state to RDF/Turtle and writes it to the Solid Pod. This is the "canonical" linked data representation. The Solid Pod is the long-term archive and interoperability layer, not the real-time sync layer.

### Why Not Use Solid Pod Directly for Sync?

Solid Pods use HTTP REST (LDP). They're great for storage and sharing but not for real-time multi-device sync:
- No built-in conflict resolution
- Polling-based (Solid Notifications is still maturing)
- High latency for offline→online sync bursts

CRDTs via Automerge solve the hard sync problem; Solid solves the data ownership/interoperability problem. They're complementary.

### Automerge Document Structure

```typescript
import { next as Automerge } from '@automerge/automerge';

interface InventoryDoc {
  items: { [shortId: string]: Item };
  locations: { [id: string]: Location };
  sightings: { [id: string]: Sighting };
  preGeneratedIds: { [id: string]: PreGeneratedId };
}

// Create and modify
let doc = Automerge.init<InventoryDoc>();
doc = Automerge.change(doc, 'Add new item', d => {
  d.items['za3rbam'] = {
    shortId: 'za3rbam',
    name: 'Bosch Drill',
    custodyState: 'checked-in',
    // ...
  };
});
```

### Auth & Permissions

- Each household member authenticates with their Solid WebID
- The Automerge sync server can use simple shared-secret or Solid-based auth
- All household members have read/write access to the shared inventory
- Personal items can be marked as `visibility: 'private'` (only visible to owner)

### Sync Server (NixOS)

The automerge-repo sync server is a small Node.js process:

```nix
# NixOS module sketch
services.solidhaus-sync = {
  enable = true;
  port = 3030;
  package = pkgs.nodejs;
  # automerge-repo-network-websocket server
};
```

This runs alongside your existing Solid pod (CSS) and other infrastructure.

### Future: NextGraph

If NextGraph reaches production readiness, it could replace the entire Automerge + Solid Pod stack with a single integrated solution: CRDT-native RDF, E2EE, P2P sync, SPARQL queries — all in one. Keep monitoring.

---

## 7. Updated Project Structure (SvelteKit)

```
solidhaus/
├── src/
│   ├── routes/
│   │   ├── +layout.svelte          # App shell, bottom nav
│   │   ├── +layout.ts              # SSR disabled
│   │   ├── +page.svelte            # Dashboard
│   │   ├── scan/
│   │   │   └── +page.svelte        # Scanner view
│   │   ├── items/
│   │   │   ├── +page.svelte        # Item list
│   │   │   ├── new/+page.svelte    # Create item
│   │   │   └── [id]/
│   │   │       ├── +page.svelte    # Item detail
│   │   │       └── edit/+page.svelte
│   │   ├── locations/
│   │   │   └── +page.svelte        # Location tree
│   │   ├── labels/
│   │   │   └── +page.svelte        # Label sheet generator + print queue
│   │   └── settings/
│   │       └── +page.svelte        # Settings, sync status, pod config
│   ├── lib/
│   │   ├── components/
│   │   │   ├── Scanner.svelte
│   │   │   ├── ItemCard.svelte
│   │   │   ├── ItemForm.svelte
│   │   │   ├── LocationPicker.svelte
│   │   │   ├── LocationTree.svelte
│   │   │   ├── QuantitySlider.svelte   # For consumables
│   │   │   ├── ConfidenceBadge.svelte
│   │   │   ├── CustodyBadge.svelte
│   │   │   ├── LabelPreview.svelte
│   │   │   ├── BottomNav.svelte
│   │   │   └── PhotoCapture.svelte
│   │   ├── data/
│   │   │   ├── db.ts                # IndexedDB
│   │   │   ├── items.ts
│   │   │   ├── locations.ts
│   │   │   ├── sightings.ts
│   │   │   └── labels.ts           # Pre-generated ID management
│   │   ├── sync/
│   │   │   ├── automerge.ts         # Automerge doc management
│   │   │   ├── repo.ts             # automerge-repo setup
│   │   │   └── solid-export.ts     # Periodic RDF export to Solid Pod
│   │   ├── solid/
│   │   │   ├── auth.ts
│   │   │   ├── rdf.ts
│   │   │   └── pod.ts
│   │   ├── scanning/
│   │   │   ├── detector.ts          # Barcode detection (native + web)
│   │   │   └── parser.ts           # ID extraction from barcodes
│   │   ├── printing/
│   │   │   ├── labelSheet.ts        # PDF label sheet generation
│   │   │   ├── tapeStrip.ts        # P-touch tape strip generation
│   │   │   └── printServer.ts      # HTTP print server client
│   │   ├── stores/
│   │   │   ├── inventory.svelte.ts  # Svelte 5 runes-based stores
│   │   │   ├── scan.svelte.ts
│   │   │   ├── sync.svelte.ts
│   │   │   └── settings.svelte.ts
│   │   ├── types/
│   │   │   ├── item.ts
│   │   │   ├── location.ts
│   │   │   ├── sighting.ts
│   │   │   └── quantity.ts
│   │   ├── ontology/
│   │   │   ├── solidhaus.ts         # Namespace constants
│   │   │   └── namespaces.ts
│   │   └── utils/
│   │       ├── id.ts                # nanoid generator
│   │       ├── confidence.ts
│   │       └── format.ts           # Quantity formatting ("400ml / 1L")
│   └── app.html
├── static/
│   ├── manifest.json
│   └── icons/
├── ontology/
│   └── solidhaus.ttl
├── android/                         # Capacitor Android project
├── ios/                            # Capacitor iOS project
├── svelte.config.js
├── capacitor.config.ts
├── vite.config.ts
├── tailwind.config.ts
├── package.json
└── tsconfig.json
```

---

## 8. Updated IndexedDB Schema (Items)

```typescript
interface Item {
  shortId: string;                // 7-char nanoid
  name: string;
  description: string;
  category: string;
  brand: string;
  serialNumber: string;
  color: string;
  purchaseDate: string | null;

  // Item type
  itemType: 'durable' | 'consumable' | 'disposable' | 'perishable'
          | 'media' | 'clothing' | 'document' | 'container';

  // Quantity (for consumables/perishables)
  currentQuantity: number | null;
  originalQuantity: number | null;
  quantityUnit: string | null;       // "ml", "g", "pcs", "sheets", "%"
  lowThreshold: number | null;
  expiryDate: string | null;         // ISO date

  // Barcode
  barcodeUri: string;                // "https://haus.toph.so/za3rbam"
  barcodeFormat: 'qr' | 'datamatrix' | 'code128';
  photoIds: string[];

  // Location tracking
  lastSeenAt: string | null;
  lastSeenTimestamp: string | null;
  lastUsedAt: string | null;
  supposedToBeAt: string | null;
  locationConfidence: 'confirmed' | 'likely' | 'assumed' | 'unknown';

  // Custody state
  custodyState: 'checked-in' | 'checked-out';
  checkedOutSince: string | null;
  checkedOutReason: 'in-use' | 'in-transit' | 'lent' | 'in-repair' | 'temporary' | 'consumed' | null;
  checkedOutFrom: string | null;
  checkedOutTo: string | null;
  checkedOutNote: string | null;

  // Storage
  storageTier: 'hot' | 'warm' | 'cold';
  storageContainerId: string | null;
  storageContainerLabel: string | null;

  // Label
  labelPrinted: boolean;
  labelPrintedAt: string | null;
  labelBatchId: string | null;       // which pre-gen batch

  // Metadata
  createdAt: string;
  updatedAt: string;
  tags: string[];
  createdBy: string | null;          // WebID of creator (multi-user)
}
```

---

## 9. Summary of All Decisions

| Decision | Choice | Rationale |
|----------|--------|-----------|
| ID length | 7 characters | More headroom for pre-generation batches |
| ID alphabet | Lowercase + digits, no ambiguous | Easier to type in URIs |
| QR content | `https://haus.toph.so/{id}` | Works everywhere, degrades gracefully |
| Custom scheme | `haus://` (bonus, native only) | Direct app launch when native app installed |
| Labels | Pre-printed sheets/strips | Faster than on-demand, batch workflow |
| Framework | SvelteKit 5 + Capacitor | Svelte preference, native features via Capacitor |
| Native mobile | Capacitor (not Svelte Native) | Svelte Native doesn't exist in usable form |
| Desktop | Tauri 2 (future) | Rust backend, SvelteKit frontend, officially supported |
| Multi-user sync | Automerge (CRDT) | Conflict-free offline-first sync between household members |
| Data ownership | Solid Pod (RDF export) | Long-term archive, interoperability, data sovereignty |
| Real-time sync | automerge-repo WebSocket server | Low-latency device-to-device sync |
| Barcode scanning (native) | @capacitor-mlkit/barcode-scanning | ML Kit is fast, supports all formats |
| Barcode scanning (web) | Barcode Detection API + ZXing | Progressive enhancement |
| Item types | durable/consumable/disposable/perishable/... | Naturally extends to pantry tracking |
| Quantity tracking | currentQuantity + unit + threshold | Consumables need "how much is left" |
| Printing | Pre-gen PDF sheets + P-touch strips via print server | Batch workflow, NixOS service |