refactor: remove GitLab CI config and docs after full Gitea migration

- Delete .gitlab-ci.yml (replaced by .gitea/workflows/ci.yml)
- Delete docs/deployment/gitlab.md (superseded by gitea.md)
- Update audit rules to reference .gitea/workflows/*.yml
- Update validate_audit.py to check Gitea CI paths
- Clean up GitLab references in gitea.md, mkdocs.yml, .dockerignore
- Mark IPv6 AAAA records as completed in hetzner docs

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

.audit-rules/compliance.yaml

@@ -122,10 +122,9 @@ rules:
       type: file_exists
       paths:
         - ".github/PULL_REQUEST_TEMPLATE.md"
-        - ".gitlab/merge_request_templates/*.md"
         - "CONTRIBUTING.md"
         - ".github/workflows/*.yml"
-        - ".gitlab-ci.yml"
+        - ".gitea/workflows/*.yml"
       message: "Code review process must be documented/enforced"
 
   - id: COMP-POL-002
@@ -138,8 +137,7 @@ rules:
         - ".github/CODEOWNERS"
         - "CODEOWNERS"
         - ".github/workflows/*.yml"
-        - ".gitlab-ci.yml"
-        - ".gitlab-ci.yml"
+        - ".gitea/workflows/*.yml"
       message: "Document change approval requirements"
 
   - id: COMP-POL-003
@@ -166,7 +164,7 @@ rules:
       type: file_exists
       paths:
         - ".github/workflows/ci.yml"
-        - ".gitlab-ci.yml"
+        - ".gitea/workflows/*.yml"
         - "pytest.ini"
         - "pyproject.toml"
       patterns:
@@ -181,7 +179,7 @@ rules:
       type: file_exists
       paths:
         - ".github/workflows/*.yml"
-        - ".gitlab-ci.yml"
+        - ".gitea/workflows/*.yml"
       patterns:
         - "deploy|release"
       message: "Deployment process must be automated and logged"