feat: branch/PR naming standard CI check

Composite action that validates head branch and PR title against the
fritzlab naming standard (role/bug-id/kebab + [bug-id] titles).
Always exits 0 (warn-only) until the Bugs system is live.

- check.sh: validation logic (branch form, title form, bug-id cross-check)
- action.yaml: composite action wrapping check.sh
- tests/run: 20-case test matrix (valid/invalid/chore/mismatch/dfritz)
- .gitea/workflows/test.yaml: CI that runs the test suite

Closes fritzlab/agenthub#559

README.md

@@ -0,0 +1,67 @@
+# action/check-naming
+
+Composite Gitea Action that validates a pull request's head branch name
+and title against the fritzlab naming standard. Always exits 0 —
+warn-only until the Bugs tracking system is live (see
+[fritzlab/agenthub#557](https://code.fritzlab.net/fritzlab/agenthub/issues/557)).
+
+## Standard
+
+```
+Branch:   <role>/bug-<id>/<kebab-description>     e.g. dev/bug-x7k2m9/fix-terminal-resize
+Chore:    chore/<kebab-description>               bug-less trivia only (dep bumps, typos, CI tweaks)
+Title:    [bug-x7k2m9] Fix terminal resize loss   (chore PRs: no [bug-id] prefix)
+```
+
+- `<role>` must be a roster handle: `dev` | `ux` | `ops` | `security` | `perf` | `architect` | `support`
+- `<bug-id>` is `bug-` followed by lowercase alphanumeric characters
+- `<kebab-description>` is lowercase alphanumeric with hyphens, starting with a letter or digit
+- When both the branch and the title carry a bug-id they **must match**
+- Break-glass: PRs authored by `dfritz` are exempt from all checks
+
+## Usage
+
+```yaml
+jobs:
+  naming:
+    runs-on: fritzlab
+    timeout-minutes: 5
+    continue-on-error: true   # non-required until Bugs cutover
+    steps:
+      - uses: https://code.fritzlab.net/action/check-naming@v1
+        with:
+          head-branch: ${{ github.head_ref }}
+          pr-title: ${{ github.event.pull_request.title }}
+          pr-author: ${{ github.event.pull_request.user.login }}
+```
+
+## Inputs
+
+| Name | Required | Description |
+|---|---|---|
+| `head-branch` | yes | Head branch name — `github.head_ref` |
+| `pr-title` | yes | PR title — `github.event.pull_request.title` |
+| `pr-author` | no | PR author login — `github.event.pull_request.user.login`; `dfritz` is exempt |
+
+## Behavior
+
+The check validates two things:
+
+1. **Branch form** — must be `<role>/bug-<id>/<kebab>` or `chore/<kebab>`.
+   Unknown roles, missing `bug-` segment, uppercase bug-ids, and empty
+   kebab descriptions all produce a `WARN[check-naming]` log line.
+
+2. **Title form** — for a `role/bug` branch the title should start with
+   `[bug-<id>] `. For a `chore` branch the title should have no `[bug-id]`
+   prefix. If both carry a bug-id they must match.
+
+All violations print a `WARN[check-naming]: ...` line. The step always
+exits 0 so it cannot block a PR. To harden to required after the Bugs
+cutover: remove `continue-on-error: true` from the consuming workflow
+and add the job's context to the repo's `status_check_contexts`.
+
+## Tests
+
+```
+bash tests/run
+```