docs: add AGENTS.md and document issue-driven workflow

- Add AGENTS.md as the cross-agent entry point (lean; points to
  .gooserules and docs/AI_* for detail)
- Document the Forgejo issue-driven workflow (report → triage →
  implement → close) and API patterns in .gooserules
- Add Forgejo step to the pre-change checklist
- Gitignore .forgejo-token

.gooserules

@@ -76,12 +76,51 @@ cd web/normogen-web && npm test
 - Auth: JWT with middleware on protected routes
 - Testing: cargo test, npm test, integration scripts
 
+## Issue-Driven Workflow
+
+The Forgejo issue tracker at `https://gitea.soliverez.com.ar/alvaro/normogen`
+is the source of truth for bugs and features. The API token lives in
+`.forgejo-token` (gitignored; never commit or echo its value).
+
+### Lifecycle
+1. **Reporting** — the user files issues as they encounter bugs or conceive
+   features, either directly in Forgejo or by describing them in chat (then the
+   agent creates the issue). Aim for one concern per issue.
+2. **Triage** — when picking up work, the agent lists open issues
+   (`GET /api/v1/repos/alvaro/normogen/issues`), reads them, asks clarifying
+   questions as needed, and proposes a plan in the issue (or chat for small
+   items) before writing code.
+3. **Implementation** — work in chunks tied to issues. Reference the issue
+   number in branch names (`fix/123-...`, `feat/456-...`) and commit messages
+   (`fix(medication): ... (#123)`). Push progress as comments on the issue for
+   anything non-trivial or spanning multiple sessions.
+4. **Closure** — close the issue with a comment summarizing what was done and
+   pointing at the relevant commits/PR. Don't close until the change is
+   verified (tests pass) and merged/pushed.
+
+### API usage patterns
+- Auth header: `Authorization: token $(cat .forgejo-token)`
+- Create issue: `POST /api/v1/repos/alvaro/normogen/issues` with JSON
+  `{title, body, labels}` (labels must exist first; create via
+  `POST /api/v1/repos/alvaro/normogen/labels`).
+- Add a comment: `POST /api/v1/repos/alvaro/normogen/issues/{index}/comments`
+- Close an issue: `PATCH /api/v1/repos/alvaro/normogen/issues/{index}` with
+  `{"state": "closed"}` (ideally after a summary comment).
+
+### Conventions
+- Use conventional-commit prefixes in titles where natural
+  (`fix:`, `feat:`), but keep titles human-readable.
+- Add the `bug` / `feature` / `enhancement` label when creating issues if those
+  labels exist; otherwise leave unlabelled rather than failing.
+- Never paste the token into commit messages, issue bodies, comments, or chat.
+
 ## Before Making Changes
 
 1. Read [AI_QUICK_REFERENCE.md](docs/AI_QUICK_REFERENCE.md)
 2. Check [product/STATUS.md](docs/product/STATUS.md) for current progress
-3. Review existing code patterns
-4. Plan your approach
+3. **Check open Forgejo issues** for the current task and its discussion
+4. Review existing code patterns
+5. Plan your approach
 
 ## Common Workflows