docs: add community governance and contribution guidelines

- Add CONTRIBUTING.md with TDD requirements, PR workflow, and AI usage
  policy
- Add CODE_OF_CONDUCT.md based on Contributor Covenant
- Add SECURITY.md with vulnerability reporting scope and process
- Add AGENTS.md with AI usage policy for human contributors and AI
  agents
- Add CLAUDE.md to require reading AGENTS.md before any work
- Add Gitea issue templates for bug reports and feature requests
- Add pull request template with TDD and code quality checklist

.gitea/ISSUE_TEMPLATE/DOCUMENTATION-ISSUE.yml

@@ -0,0 +1,59 @@
+name: Documentation Issue
+description: Report missing, incorrect, or unclear documentation
+title: "[Docs]: "
+labels: ["documentation"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Use this template to report issues in the documentation, such as missing
+        content, incorrect information, or unclear explanations.
+  - type: dropdown
+    id: doc-location
+    attributes:
+      label: Documentation location
+      description: Which part of the documentation is affected?
+      options:
+        - README
+        - CONTRIBUTING.md
+        - Wiki
+        - rustdoc (inline code documentation)
+        - API documentation (OpenAPI / Swagger UI)
+        - specs/ (specifications and constitution)
+        - docs/ (guides)
+        - Other
+    validations:
+      required: true
+  - type: input
+    id: doc-page
+    attributes:
+      label: Specific page or section
+      description: Link or name of the specific page, section, or function affected
+      placeholder: "e.g. docs/cors-configuration.md § Fail-Safe Defaults"
+  - type: dropdown
+    id: issue-type
+    attributes:
+      label: Type of issue
+      options:
+        - Missing documentation (undocumented feature or behaviour)
+        - Incorrect information
+        - Outdated information
+        - Unclear or confusing explanation
+        - Broken link
+        - Other
+    validations:
+      required: true
+  - type: textarea
+    id: description
+    attributes:
+      label: Description
+      description: Describe the documentation issue in detail
+      placeholder: "The section on X does not explain Y, which is needed to Z..."
+    validations:
+      required: true
+  - type: textarea
+    id: suggested-fix
+    attributes:
+      label: Suggested improvement
+      description: If you have a suggestion for how to fix or improve the documentation, please share it
+      placeholder: "The section should clarify that..."