Restructure tea skill into a plugin with a mandatory-login guard

Convert the standalone `tea` skill into a skills-dir plugin so commands are
namespaced and an enforcement hook can ship with it:

- /tea:login  — pin the project Gitea login into .claude/settings.local.json
- /tea:use    — tea CLI reference (was the old root SKILL.md), with the
                login rule slimmed since the hook now enforces it
- hooks/tea-guard.sh — PreToolUse(Bash) guard: blocks any `tea` command that
  touches Gitea unless it carries --login and $GITEA_LOGIN is set. Exempts
  `tea logins list` and `tea --version/--help` so /tea:login can bootstrap.

References moved under skills/use/references/. `claude plugin validate` passes;
guard unit-tested across allow/block cases.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

skills/use/SKILL.md

@@ -0,0 +1,102 @@
+---
+name: use
+description: Reference docs for the `tea` CLI — Gitea's command-line client. Load when the user asks about Gitea repos, issues, pulls, releases, actions, or other Gitea entities, to look up the right `tea` command and flags. Every tea call must carry --login "$GITEA_LOGIN" (enforced by the tea-guard hook; set it with /tea:login).
+---
+
+# /tea:use — tea CLI reference
+
+Reference material for the `tea` CLI (Gitea's official command-line client).
+Use these docs to look up commands, flags, filters, and output fields before
+running `tea` via Bash.
+
+## Login is mandatory (enforced)
+
+Every `tea` invocation that touches Gitea MUST include `--login "$GITEA_LOGIN"`
+(or `-l "$GITEA_LOGIN"`). This is enforced by the **`tea-guard`** PreToolUse
+hook — a `tea` command without `--login` is blocked before it runs. If
+`$GITEA_LOGIN` is unset, run **`/tea:login`** to pin one.
+
+Why: without `--login`, `tea` silently falls back to the machine's default
+login (possibly the user's personal account) and writes under the wrong
+identity. The login value is pinned per-project in `.claude/settings.local.json`
+under `env.GITEA_LOGIN`. Only `tea logins list` and `tea --version/--help` are
+exempt from the guard.
+
+## How to use
+
+1. Identify the entity in the request: issues, pulls, labels, milestones,
+   releases, times, repos, branches, actions, webhooks, comments,
+   notifications, etc.
+2. Find the matching command in the index below.
+3. Run it via Bash with the login, e.g.
+   `tea issues list --login "$GITEA_LOGIN" --repo owner/repo --state open`.
+
+`tea` auto-detects owner/repo from `$PWD` inside a git repo; otherwise pass
+`--repo owner/repo` (or `-r`). Login is **not** auto-detected — it is pinned
+per-project (see `/tea:login`). Config lives in `$XDG_CONFIG_HOME/tea`.
+
+## Index
+
+- [tea CLI overview](references/tea/index.md) — global flags, common options, output formats
+- [ENTITIES](references/tea/entities.md) — issues, pulls, labels, milestones, releases, times, repos, branches, actions, webhooks, comment
+- [HELPERS](references/tea/helpers.md) — open, notifications, clone, api
+- [MISC](references/tea/misc.md) — whoami, admin
+- [SETUP](references/tea/setup.md) — logins, logout, ssh-keys
+
+## Rich payloads — write to `$PWD/tmp/` first, then `tea api`
+
+Entity subcommands (`tea comment`, `tea issues create`, `tea pulls create`, …)
+are built for humans at a TTY. With a large or formatted body they can hang
+silently — an empty-looking positional arg triggers `$EDITOR` fallback, or a
+scope/confirm prompt waits on a TTY that doesn't exist. The harness eventually
+kills the process (e.g. exit 144 = 128 + SIGURG on macOS).
+
+**Rule:** for any non-trivial body (multi-line, or containing markdown / code
+fences / backticks / pipes / tables), bypass entity commands. Save the full
+request payload to `$PWD/tmp/` first, then POST via `tea api`.
+
+### Procedure
+
+1. Ensure the target dir exists: `mkdir -p tmp/{kind}` where `{kind}` is
+   `comment`, `issue`, `pull`, `release`, etc.
+2. Write the **complete request body as JSON** to `$PWD/tmp/{kind}/<slug>.json`.
+   One file = one request. Use a quoted heredoc to avoid shell expansion:
+   ```bash
+   mkdir -p tmp/comment
+   cat > tmp/comment/issue-60.json <<'EOF'
+   {"body": "## Heading\n\nMulti-line markdown with `code`, | tables |, and ```fences```."}
+   EOF
+   ```
+   Newlines inside the body must be encoded as `\n` in the JSON string. If
+   composing programmatically, pipe through
+   `jq -Rs '{body: .}' < body.md > tmp/comment/issue-60.json`.
+3. POST with `tea api`, passing the file with `-d @<path>`:
+   ```bash
+   tea api --login "$GITEA_LOGIN" \
+     -X POST -d @tmp/comment/issue-60.json \
+     repos/{owner}/{repo}/issues/60/comments
+   ```
+4. Keep the file. `tmp/` should be gitignored; the saved payload is useful for
+   retries, edits (`PATCH`), and debugging failed posts.
+
+### Common endpoints
+
+| Action | Method + endpoint |
+|---|---|
+| Comment on issue/PR | `POST repos/{owner}/{repo}/issues/{n}/comments` |
+| Edit comment | `PATCH repos/{owner}/{repo}/issues/comments/{id}` |
+| Create issue | `POST repos/{owner}/{repo}/issues` |
+| Edit issue/PR body or title | `PATCH repos/{owner}/{repo}/issues/{n}` |
+| Create PR | `POST repos/{owner}/{repo}/pulls` |
+| Create release | `POST repos/{owner}/{repo}/releases` |
+
+Short single-line bodies (e.g. `tea comment 42 "lgtm" --login "$GITEA_LOGIN"`)
+are still fine via entity commands.
+
+## Tips
+
+- Pass `-o json` for structured output when parsing programmatically.
+- Use `--fields, -f` to narrow columns.
+- Pagination: `--page, -p <n>` and `--limit, --lm <n>` (defaults 1 / 30).
+- If a `tea` command is blocked by `tea-guard`, you forgot `--login` or
+  `$GITEA_LOGIN` is unset — add the flag or run `/tea:login`.