feat(狀態回報): 收尾寫一筆 skill-end 事件

現行紀錄只記「被叫用」，沒有成敗也沒有結束碼。跑完整輪的技能與開場就
中止的技能，在紀錄裡長得一模一樣。

start 由技能用量 hook 順手發，不必改技能文件。end 只能由技能自己在收尾
步驟寫——hook 接在技能工具呼叫上，而實際工作發生在之後的模型輪次，它在
原理上看不到成敗。有 start 沒有配對的 end，就是那一輪中止了。

status 五選一，每支技能各自寫明什麼情況選哪一個。找不到回報腳本就安靜
跳過，回報失敗一律不改變技能自己的結論。

skills/repo-sync/SKILL.md

@@ -16,3 +16,18 @@ description: Batch-sync all readable repos of a chosen Gitea owner into the work
 
    Done when every repo's sub agent has returned one of those outcomes; one repo failing never cancels the others.
 5. Report the sync result for every repo: cloned, updated, PR table row, or the failure reason. Done when every `{repo}` from step 3 carries one of those four results, and all PR rows share one table when more than one PR exists.
+6. **Record how the run ended.** This is the last thing this skill does, and it runs on every path out of the skill, the ones that stop at step 1 included. Call
+
+   `jsc-hooks/tools/report-status.sh skill-end jsc-gitea:repo-sync {status} {exit code} [detail]`
+
+   `{exit code}` is the exit code of whatever decided the outcome, and `0` when nothing failed. `{detail}` is one short line, no more than 200 characters — the repo counts fit there, the per-repo list does not. **If the script is not on this machine, skip this step in silence and finish the run as it stood** — missing infrastructure is not a failure, and a reporting call may never change what this skill returns or reports.
+
+   | status | When this skill uses it |
+   | --- | --- |
+   | `ok` | Every repo from step 3 came back `cloned`, `updated`, or dirty with its PR opened |
+   | `blocked` | Nothing could be listed, so no repo was touched: `GITEA_HOST` or `GITEA_TOKEN` was required and the user gave none, or `owners` exited 0 with no owner this key can read |
+   | `failed` | The listing broke mid-run — `owners` or `repos` returned 7 or 8 — or every repo in step 4 came back `failed`. No repo reached the working directory |
+   | `degraded` | Some repos synced and some did not: at least one `failed {reason}` next to at least one `cloned`, `updated` or PR row. One repo failing never cancels the others, so the run finishes with part of the workspace missing |
+   | `aborted` | The user named no owner at step 2, or stopped the run before step 4 started |
+
+   Completion condition: exactly one `skill-end` line was recorded for this run, or the script was absent and the run finished without it.