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/FEATURE-REQUEST.yml

@@ -0,0 +1,40 @@
+name: Feature Request
+description: Request a new feature
+title: "[Feature Request]: "
+labels: ["enhancement"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to request a new feature!
+  - type: checkboxes
+    id: pre-submission
+    attributes:
+      label: Pre-submission checklist
+      options:
+        - label: I have searched existing issues and this feature has not already been requested
+          required: true
+  - type: textarea
+    id: feature-description
+    attributes:
+      label: New feature
+      description: Description of the new feature
+      placeholder: "Describe the feature you would like to see added to STA"
+    validations:
+      required: true
+  - type: textarea
+    id: feature-reason
+    attributes:
+      label: Why this new feature
+      description: Describe why this new feature should be added to STA
+      placeholder: "Describe the problem this feature would solve or the value it would add"
+    validations:
+      required: true
+  - type: textarea
+    id: ideas-implementation
+    attributes:
+      label: Implementation ideas and additional thoughts
+      description: Do you have an idea on how to implement it?
+      placeholder: "It could be implemented by..."
+    validations:
+      required: false