fix(worker): start with a repository-only token

The start-up check read the token's account with GET /user, which needs the
read:user scope. A token with only repository scope, which is all the worker
needs, got 403 and the worker exited in a restart loop. On 403 it now
names the commit author from BOT_NAME (default gbr-bot) and still checks
push access on the games repo.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

BUILDER.md

@@ -46,6 +46,7 @@ All through environment variables; nothing about where it runs lives in this rep
 | `OLLAMA_URL` | Ollama for the model (or `MODEL_PROVIDER=gemini` with `GEMINI_API_KEY`) |
 | `SEARXNG_URL`, `READER_URL` | A SearXNG instance (JSON API) and a page-to-text reader (`READER_URL/<page url>`) |
 | `MODEL`, `POLL_INTERVAL`, `WORKER_NAME`, `WORK_DIR` | Optional: model name, poll interval (20s), name shown in the panel, work folder |
+| `BOT_NAME` | Optional: commit author when the token can't read its own account (no `read:user` scope); default `gbr-bot` |
 
 ## Running a build by hand