v3.13.0 - Identity Management & Wiki Consolidation

- New script: `find-unregistered-users.js` - Detect abandoned Signal accounts
  - Uses `UNREGISTERED_FAILURE` response to find accounts trust command misses
  - Caches results for fast subsequent operations
  - `--scan` to detect, `--remove` to clean up, `--list` to view cached results
- Supporting scripts: `trust-all-users.js`, `remove-failed-users.js`, `list-failed-users.js`
- Key discovery: `sendReceipt` reveals true registration status vs `trust` command

- Consolidated all wiki content to dedicated wiki repository
- New wiki page: Safety Numbers & Identity - explains trust concepts and scripts
- Expanded sidebar with Games, Storage, Development, and Administration sections

- Removed `docs/wiki/` directory (content moved to wiki repo)
- All documentation now lives in the wiki for easier community editing

- `scripts/find-unregistered-users.js` - Main unregistered user detection
- `scripts/trust-all-users.js` - Bulk trust identities
- `scripts/remove-failed-users.js` - Remove trust failures from groups
- `scripts/list-failed-users.js` - List failed users with group counts
- `scripts/check-group-members.js` - Check specific group for failures
- `scripts/list-group-signal.js` - List group members from signal-cli