Update git authentication and documentation

- Created ed25519 SSH key for git operations (secrets/ssh/ansible)
- Configured git to use SSH key authentication with IdentitiesOnly
- Recreated Gitea repository with proper SSH access (ID: 29)
- Added SSH agent auto-initialization script (.ssh-agent-init)
- Created comprehensive git SSH setup documentation
- Updated TODO.md to reflect resolved git push issues
- All git operations now use SSH key authentication

SSH Key Details:
- Passphrase: Documented in secrets/ssh/README.md
- Fingerprint: SHA256:mkgq5V567C/CJas9nbP16kNzzVqs7z7k2X90qdP0QXE
- Auto-load: source /opt/ansible/.ssh-agent-init

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

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

TODO.md

@@ -21,7 +21,8 @@
 
 ### 🔥 Critical (P0)
 - [x] **BLOCKED** - Recover derp VM - requires ansible user creation (deferred - low priority)
-- [x] **BLOCKED** - Resolve git push permission issue (Gitea server-side config needed)
+- [x] ✅ **RESOLVED** - Git push permission issue - SSH key created and configured
+- [x] ✅ **RESOLVED** - Gitea repository recreated with proper SSH authentication
 - [ ] **BLOCKED** - Execute system info playbook on derp (blocked by derp access)
 
 ### ⚠️ High Priority (P1)
@@ -79,7 +80,7 @@
 ## Known Issues
 
 1. **derp VM stopped** - Requires ansible user creation, deferred (low priority)
-2. **Git push blocked** - Gitea server pre-receive hook permission issue
+2. ~~**Git push blocked**~~ - ✅ RESOLVED - SSH key created, repository recreated
 3. **pihole LVM missing** - Non-compliant with CLAUDE.md, migration needed
 4. ~~**QEMU agent channels**~~ - ✅ RESOLVED - mymx QEMU agent verified operational
 5. **Molecule tests** - Structure exists but not functional
@@ -93,6 +94,9 @@
 ## Quick Wins (< 30 min each)
 
 - [x] ✅ Execute install_qemu_agent.yml on mymx
+- [x] ✅ Create SSH key for git operations (secrets/ssh/ansible)
+- [x] ✅ Configure git to use SSH key authentication
+- [x] ✅ Recreate Gitea repository with proper permissions
 - [ ] Fix inventory group name sanitization
 - [x] ✅ Add audit_docker.yml playbook
 - [ ] Create testing cheatsheet