feat: add the tea-runner execution agent

The skills carry meaning, the scripts carry work. Splitting the second
half onto a cheap model keeps the main session's context for the part
that needs judgement.

tea-runner is a Haiku subagent with Bash/Read/Grep/Glob/Skill and
nothing else. It loads /tea:sync or /tea:issue for the command table
rather than carrying its own copy, so the skills stay the single source
of truth for the script surface.

It executes and reports; it decides nothing. No Edit and no Write, so an
issue body is out of reach. No raw tea, no --force, no closing or
retitling, no pushing past the set it was handed, one retry maximum. A
failed validation, a missing type, an unpushed dependency come back as a
question in a `blocked:` line. The reply is a fixed receipt — commands
with ok/FAIL, touched paths, stderr verbatim — never a payload dump.

Knowledge still flows one way: nothing under skills/ knows the agent
exists, and deleting agents/ changes nothing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -25,6 +25,9 @@ skills/sync     BRIDGE     map.py    md <-> Gitea JSON, pure functions, no I/O
                            _gitea.py login pin, tea api, pagination, filters
 skills/use      REFERENCE  tea CLI docs for everything that is not an issue
 skills/auth     IDENTITY   pin the login the whole tracker side runs under
+      ▲
+      │ calls
+agents/         EXECUTION  tea-runner: runs the scripts, reports a receipt
 ```
 
 `skills/issue` never imports from `skills/sync`. Delete `skills/sync` and the
@@ -56,6 +59,12 @@ the domain layer, it is in the wrong place.
   - `scripts/pull.py`, `push.py`, `remote.py`, `comment.py`
 - `skills/use` — `tea` CLI reference for everything that is not an issue
   (`/tea:use`); `references/tea/` holds the command docs
+- `agents/tea-runner.md` — subagent on Haiku that executes the scripts and
+  returns a compact receipt. Delegate batches (bulk pull, push a named set,
+  bootstrap labels, rebuild the index), never the thinking: it has no `Edit`
+  and no `Write`, may not `--force`, and may not decide what an issue says.
+  Delegating a single call costs more than running it inline — the win is the
+  loop, the retry, and the error triage.
 - `hooks/` — PreToolUse hooks: `tea-guard` blocks or rewrites `tea` invocations
   that don't use the pinned login; `agents-sync` keeps every directory canonical
   (`AGENTS.md` real file, `CLAUDE.md` symlink to it)