Add CLI channel command group for channel key management

New commands:
- stegasoo channel generate [--save|--save-user]
- stegasoo channel show [--key KEY]
- stegasoo channel status
- stegasoo channel qr [--key KEY] [-o FILE] [--format ascii|png]
- stegasoo channel clear [--project|--user]

Features:
- ASCII QR code output for terminal display
- PNG QR code export for sharing
- JSON output mode (--json flag)
- Explicit key override for all commands

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

PLAN-4.1.0.md

@@ -8,7 +8,7 @@ Version 4.1.0 is a feature release focusing on small-group deployment improvemen
 
 1. ~~**Multi-User Support** - Admin can create up to 16 users for shared deployments~~ ✅ DONE
 2. **Channel Key QR** - Easy visual sharing of channel keys via QR codes
-3. **CLI Channel Commands** - Manage channel keys from command line
+3. ~~**CLI Channel Commands** - Manage channel keys from command line~~ ✅ DONE
 4. **Advanced Tools** - Image/stego utilities (TBD)
 
 ---
@@ -426,6 +426,6 @@ Or simpler: detect on startup, update schema automatically (current pattern).
 ## Progress
 
 - [x] Multi-User Support (commit 7b33501)
-- [ ] Channel Key QR
-- [ ] CLI Channel Commands
+- [ ] Channel Key QR (Web UI)
+- [x] CLI Channel Commands
 - [ ] Advanced Tools