Fix doc tag inconsistencies and add missing ai changelog type (#114)

## Summary
- Add missing `ai` changelog fragment type to the update-documentation how-to guide (comment and table)
- Consolidate `cicd` → `ci-cd` tag on forgejo.md
- Consolidate `network` → `networking` tag on routing.md and tailscale.md

Found during random doc review via `docs-review-tags`.

Reviewed-on: https://forge.ops.eblu.me/eblume/blumeops/pulls/114

docs/reference/infrastructure/routing.md

@@ -2,7 +2,7 @@
 title: service-routing
 tags:
   - infrastructure
-  - network
+  - networking
 ---
 
 # Service Routing

docs/reference/infrastructure/tailscale.md

@@ -2,7 +2,7 @@
 title: tailscale
 tags:
   - infrastructure
-  - network
+  - networking
 ---
 
 # Tailscale

docs/reference/services/forgejo.md

@@ -3,7 +3,7 @@ title: forgejo
 tags:
   - service
   - git
-  - cicd
+  - ci-cd
 ---
 
 # Forgejo