- Add GC_MODE=false variable and --gc) case to flag parsing
- Define gc_instances() before --check block (callable before ANSI init)
- Add GC dispatch block after --check, before ANSI formatting (early exit)
- gc_instances iterates ~/.claudebox/projects/*/project-root, removes dirs
whose recorded root path no longer exists on disk
- Prints each removal and summary count to stderr (D-11, D-12, INST-04)
- Replace --bind ~/.claudebox + --symlink with direct --bind ~/.claude ~/.claude
- Add compute_canonical_root() function using git rev-parse --git-common-dir
- Add per-project INSTANCE_DIR via sha256sum[:16] of canonical git root
- Overlay projects/ with per-project hash dir for isolated conversation history
- Overlay history.jsonl and SANDBOX.md as file-level bind mounts
- Update credential mount target from ~/.claudebox to ~/.claude
- Add CLAUDE_JSON_FILE (~/.claude.json) detection and conditional bind mount
- Remove stale CLAUDE.md injection logic (D-06: user's real CLAUDE.md used)
- Update dry-run block and print_audit to reflect new mount layout
- Update SANDBOX.md heredoc to remove ~/.claudebox reference
- Add CREDS_FILE/CREDS_MOUNT detection after mkdir ~/.claudebox
- Conditional --bind in exec bwrap via BWRAP_ARGS array
- Mirror conditional bind in --dry-run display block
- Read-write mount (not ro-bind) for OAuth token refresh
- Silent skip when credentials file absent (no error/warning)
- Refactor exec bwrap to BWRAP_ARGS array for conditional mount support
