docs: add ADR index workflow, standardize all ADR formats

- Add Gitea Action to auto-update README badges and ADR table on push
- Standardize 8 ADRs from heading-style to inline metadata format
- Add shields.io badges for ADR counts (total/accepted/proposed)
- Replace static directory listing with linked ADR table in README
- Accept ADR-0030 (MFA/YubiKey strategy)

decisions/0030-mfa-yubikey-strategy.md

@@ -1,6 +1,6 @@
 # MFA and Yubikey Strategy
 
-* Status: proposed
+* Status: accepted
 * Date: 2026-02-04
 * Deciders: Billy
 * Technical Story: Enable hardware security key (Yubikey) authentication across homelab applications
@@ -52,7 +52,7 @@ WebAuthn provides the best security (phishing-resistant) and user experience (to
 
 | Application | WebAuthn Support | Current Status | Action Required |
 |-------------|------------------|----------------|-----------------|
-| Authentik | ✅ Native | ⚠️ In Progress | Configure enforcement policies |
+| Authentik | ✅ Native | ✅ Implemented | Blueprint deployed via ConfigMap |
 | Vaultwarden | ✅ Native | ✅ Implemented | None - WebAuthn enrolled |
 
 ## Authentik Configuration