Restructure docs: archive VLAN migration, update IPs to VLAN 10

Major documentation cleanup after VLAN migration completion:
- Archive 12 VLAN project docs to archive/vlan-migration/
- Archive 5 done WIP docs (VLAN proposals, AI stack, Fossorial, DNS backup)
- Create standing reference docs 08-DNS-ARCHITECTURE and 09-TAILSCALE-VPN
- Renumber docs to clean 01-09 sequence with merged CHANGELOG
- Update all active docs from stale 192.168.31.x to current VLAN 10 IPs
- Fix CSS1 (.10.9→.10.3) and ZX1 (.10.7→.10.4) IPs in hardware inventory
- Clean 06-VLAN-DEVICE-ASSIGNMENT: remove migration columns/sections, fix VLAN 25 subnet

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/archive/README.md

@@ -1,8 +1,8 @@
 # Archived Documentation
 
-> ⚠️ **OBSOLETE - DO NOT UPDATE**
+> **OBSOLETE - DO NOT UPDATE**
 
-These documents are from the legacy documentation structure (pre-2026-01-25).
+These documents are from completed projects and legacy documentation.
 They are kept for historical reference only.
 
 **For current documentation, see the parent `docs/` folder:**
@@ -10,7 +10,28 @@ They are kept for historical reference only.
 - `02-SERVICES-CRITICAL.md` - Essential services
 - `03-SERVICES-OTHER.md` - Non-critical services
 - `04-HARDWARE-INVENTORY.md` - Hardware details
-- `05-CHANGELOG.md` - Major events
+- `05-PORT-UTILIZATION.md` - Device port assignments
+- `06-VLAN-DEVICE-ASSIGNMENT.md` - VLAN device mapping
+- `07-WIFI-CAPSMAN-CONFIG.md` - WiFi and CAPsMAN settings
+- `08-DNS-ARCHITECTURE.md` - DNS failover architecture
+- `09-TAILSCALE-VPN.md` - Tailscale VPN setup
+- `CHANGELOG.md` - Change history
+
+## Subfolders
+
+### vlan-migration/
+
+12 documents from the VLAN migration project (completed 2026-01-31):
+- Migration plans (v1, v2, v3)
+- Implementation status trackers
+- Setup progress logs
+- DNS/AdGuard/Tailscale project docs (superseded by standing docs 08- and 09-)
+- Device migration worksheet
+
+### Legacy Docs (root archive/)
+
+- Pre-2026-01-25 documentation structure
+- Completed WIP items (VLAN proposals, AI stack, Fossorial tunnels)
+- Historical changelogs
 
 **Do not reference these archived documents for current state.**
-All relevant information has been migrated to the new structure.