Add Gitea integration for agent to push branches and open pull requests

- Implemented `register-gitea-bot.sh` to provision Gitea access token.
- Updated `maintainer.py` to support Gitea API for push and PR operations.
- Modified `install.sh` to warn if Gitea token is not provisioned.
- Enhanced documentation in `README.md`, `CLAUDE.md`, and `architecture.md` to reflect new Gitea functionality.
- Added Gitea configuration to `config.example.json`.

docs/architecture.md

@@ -38,6 +38,18 @@ feeds the agent state and relays its results.
   `fix-only` or `notify`.
 - **Matrix transport**: dedicated bot `@maintainer:semprini.me` (created via the
   Synapse registration shared secret) in a private room with `@paul:semprini.me`.
+- **Code changes go through pull requests.** When the agent edits tracked files
+  it branches, pushes, and opens a PR on Gitea (`git.semprini.me`) as the
+  `claude-code` user rather than committing to `main`, giving the operator a
+  review gate. Live remediation (restart/redeploy) is *not* gated — only the git
+  change is. claude-code is an OIDC-linked, push-capable collaborator; since
+  git.semprini.me disables password login + HTTP basic auth, `register-gitea-bot.sh`
+  mints a personal access token via the gitea admin CLI inside the `user-gitea`
+  container (mirroring the Matrix bot's shared-secret pattern). A PAT still works
+  for git-over-HTTPS and the API, so no SSH exposure or core-stack change is
+  required. The daemon injects the bot's git identity + credential (`GIT_CONFIG_*`,
+  scoped to the Gitea host so it overrides the repo's own `user.*`) and the API
+  coordinates into the headless agent; the agent opens the PR itself.
 
 ## Cadence