docs: add merge priority order with security hardening as #1 priority

- Updated roadmap phase status (Phase 4 complete)
- Added merge priority table with PR #28 (security) at top
- Documented that security must merge before new services exposed
- Added deployment command reference

.planning/ROADMAP.md

@@ -13,7 +13,9 @@ None
 - ✅ **Phase 1: Foundation Setup** - Establish core NixOS configuration with flakes
 - ✅ **Phase 2: Docker Service Integration** - Integrate Docker Compose services
 - ✅ **Phase 3: AI Assistant Integration** - Enable AI-assisted infrastructure management
-- [ ] **Phase 4: Internet Access & MCP** - MCP server for web access
+- ✅ **Phase 4: Internet Access & MCP** - MCP server for web access
+- 🚨 **Security Hardening** - CRITICAL: Firewall, fail2ban, SSH hardening (PR #28)
+- [ ] **Phase 5: TAK Server** - Research, implementation, and validation
 
 
 ## Phase Details
@@ -133,8 +135,25 @@ Plans:
 
 ## Progress
 
+**Merge Priority Order** (CRITICAL - merge in this order):
+
+| Priority | PR | Description | Status | Notes |
+|----------|-----|-------------|--------|-------|
+| 🚨 1 | #28 | **Security hardening** (firewall, fail2ban, SSH) | Open | **MERGE FIRST** - protects all other services |
+| 2 | #22 | Matrix bridge dependency fix | Open | Blocks Hermes functionality |
+| 3 | #21 | Backup network creation fix | Open | Infrastructure fix |
+| 4 | #25 | Hermes voice GPU support | Open | Feature enhancement |
+| 5 | #24 | uConsole CM5 host | Open | New hardware support |
+| 6 | #23 | NixOS deployment infrastructure | Open | Deployment tooling |
+| 7 | #1 | AI worker restricted access | Open | Legacy PR (superseded by hardening) |
+
 **Execution Order:**
-Phases execute in numeric order: 1 → 2 → 3 → 4 → 5 → 6 → 7
+Phases execute in numeric order: 1 → 2 → 3 → 4 → Security → 5 → 6 → 7
+
+**Merge vs Phase Execution:**
+- PRs can merge independently (no strict phase ordering for merges)
+- **EXCEPTION:** Security hardening (#28) must merge before any new services are exposed
+- After security merge, deploy with: `nh os switch --flake .#lazyworkhorse`
 
 | Phase | Milestone | Plans Complete | Status | Completed |
 |-------|-----------|----------------|--------|-----------|