Add a gitea skill; point AGENTS.md at it

Forge usage was spread across AGENTS.md, docs/agents/issue-tracker.md, and
whatever the agent remembered about `gh`. Move the how-to-run-`tea` half into a
model-invoked skill so it loads on any issue/PR task, and leave AGENTS.md a
single line of identity plus pointers.

The skill carries only what `tea --help` cannot answer: `gh` is absent so the
harness's `issue://`/`pr://` URIs error out, issues and PRs share one index
space, rendered-box output needs `-o json`, `close` takes no `--comment`,
labels never auto-create, bodies need a heredoc, and a read without
`--comments` silently drops every comment (issue #123: 40 lines bare, 132 with
the flag). Tracker conventions and triage label strings stay in
docs/agents/, cited rather than copied.

.claude/skills/gitea/SKILL.md

@@ -0,0 +1,75 @@
+---
+name: gitea
+description: Use for every forge operation in this repo — read, create, comment on, label, close, or search an issue; create, review, merge, or check out a PR; and whenever `gh`, `issue://`, or `pr://` fails or a ticket number is ambiguous. This repo's forge is self-hosted Gitea driven by `tea`, not GitHub.
+---
+
+# Gitea, not GitHub
+
+`origin` is the self-hosted Gitea instance `gitea.violetcrown.my.id`, repo
+`sulthan/mangaBookmark`. Everything past plain git goes through
+[`tea`](https://gitea.com/gitea/tea) (0.14.2 on this machine).
+
+**`gh` is not installed**, so the harness's `issue://<n>` and `pr://<n>` URIs
+error out (`GitHub CLI (gh) is not installed`, measured 2026-08-17). There is no
+fallback to add — read tickets with `tea`.
+
+`tea` infers the repo from `origin`; auth lives in `tea login`, never a
+`GH_TOKEN`. Your Gitea username comes from `tea login list` — `tea` has no `@me`.
+
+Flags are the environment's job: run `tea <command> --help` rather than trusting
+a remembered flag. This file carries only what `--help` will not tell you.
+
+## Commands
+
+| Job | Command |
+|---|---|
+| Read | `tea issue <n> --comments` / `tea pr <n> --comments` — `--comments` is not optional |
+| List | `tea issue list --state open\|closed\|all -o json --fields index,title,body,labels,state,author` |
+| Search | `tea issue list -k "<keyword>" -L "<label>" -A "<author>"` (`-K all` also searches PRs) |
+| Create | `tea issue create -t "..." -d "..."` (`-L`, `-a` optional) |
+| Comment | `tea comment <n> "..."` |
+| Label | `tea issue edit <n> --add-labels "..."` / `--remove-labels "..."` |
+| Close | `tea issue close <n>` / `tea pr close <n>` |
+| PR | `tea pr create --head <branch> --base main -t "..." -d "..."`, `tea pr checkout <n>`, `tea pr review <n>`, `tea pr merge <n>` |
+
+## Traps
+
+- **A bare read is a truncated read.** Without `--comments`, `tea issue <n>` and
+  `tea pr <n>` print the opening body and drop every comment silently — no
+  prompt, no marker, no hint that more exists (measured 2026-08-17: issue #123
+  prints 40 lines bare, 132 with `--comments`). The comments are where the
+  decisions live and the body is usually the stalest part of the ticket, so
+  **every read that exists to understand an issue or PR passes `--comments`**,
+  and understanding means body plus all comments plus whatever ticket they point
+  at. Comment count is `tea issue list --fields index,comments`, so a read that
+  shows fewer than that is incomplete. A PR's review comments are a second
+  stream: `tea pr review-comments <n>`.
+- **One index space for issues and PRs.** A bare `#42` may be either: try
+  `tea pr 42`, fall back to `tea issue 42`. Say which one you found.
+- **Output is rendered boxes**, not plain text. Anything you parse needs
+  `-o json`, plus `--fields` to keep the payload small. `tea pr create` prints
+  the PR URL on its last line.
+- **`close` takes no `--comment`.** Comment with `tea comment <n>`, then close.
+- **Gitea will not auto-create a label.** `tea labels list` first; missing one
+  gets `tea labels create --name "..." --color "#rrggbb"` before the `edit`.
+- **Multi-line bodies go through a heredoc**, never inline escapes:
+  ```bash
+  tea issue create -t "Title" -d "$(cat <<'EOF'
+  body line one
+
+  - acceptance criterion
+  EOF
+  )"
+  ```
+- **No sub-issue and no dependency command.** Gitea's API has issue
+  dependencies, `tea` does not expose them, so parentage and blocking live as
+  body lines — the shapes are in `docs/agents/issue-tracker.md`.
+
+## Conventions this repo layers on top
+
+Ticket bodies, wayfinding issues, and the PR-as-request-surface flag:
+`docs/agents/issue-tracker.md`. Triage label strings: `docs/agents/triage-labels.md`.
+A label named there still has to exist in the tracker before `--add-labels`.
+
+Finish a forge action by stating the number you touched and its state after —
+"commented and closed #71" — so the write is checkable without a second query.