feat(agents): triage PR ergonomics — refs adcp#3121 (#95)

Mirrors adcontextprotocol/adcp#3172. Three coordinated edits to
.agents/routines/triage-prompt.md:

1. Pre-PR gate: do not declare "approved" while build is red.
2. PR body now carries a "Triage-managed PR" block documenting
   the no-iteration policy (push fixup commits or re-trigger via
   /triage on the source issue).
3. claude-triaged label applied to PR after gh pr create
   (mirrors issue label, searchable from PR list views).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: bokelley

.agents/routines/triage-prompt.md

@@ -364,7 +364,9 @@ unit tests pass.
 2. **If build or tests fail:** read the errors, fix the code,
    re-run. Cap at **2 build→fix iterations.** If still failing,
    abandon the PR and Flag for human review with the build log
-   in the comment.
+   in the comment. **Do not declare "approved" in the pre-PR
+   review block while build is red** — that's a trust-eroding
+   signal (per adcp#3121).
 3. Do **not** skip tests locally because "CI will run them." The
    point of this gate is to not ship known-broken code even as a
    draft, because (a) review noise, (b) a human reviewer may
@@ -416,8 +418,40 @@ have read the diff before a human reviewer does.
 - Branch: `claude/issue-<N>-<short-slug>`
 - Status: **draft**
 - Title: conventional-commits (`fix(router): …`, `fix: …`)
-- Body: `Closes #N`, summary, what-tested, **Pre-PR review** block with
-  security-reviewer explicitly called out, `Session:` link
+- Body, in order:
+  - `Closes #N`
+  - One-paragraph summary
+  - What-tested list (go build / vet / test / golangci-lint results)
+  - **Pre-PR review** block with both experts' one-line sign-off
+    (security-reviewer always called out for this repo's posture)
+  - **Triage-managed PR block** — append this verbatim before the
+    `Session:` link so reviewers know the iteration policy:
+
+    ```
+    > **Triage-managed PR.** This bot does not currently iterate on
+    > review comments or PR conversation threads (only on the source
+    > issue). To unblock:
+    >
+    > - **Push fixup commits directly:** `gh pr checkout <num>` →
+    >   fix → push.
+    > - **Or re-trigger:** comment `/triage execute` on the source
+    >   issue.
+    >
+    > See [adcp#3121](https://github.com/adcontextprotocol/adcp/issues/3121)
+    > for context.
+    ```
+  - `Session: https://claude.ai/code/${CLAUDE_CODE_REMOTE_SESSION_ID}`
+- **After `gh pr create` succeeds**, label the PR `claude-triaged`
+  so it's searchable from PR list views (mirrors the issue label):
+
+  ```
+  gh pr edit <PR#> --repo <owner>/<repo> --add-label claude-triaged
+  ```
+
+  (Don't apply `claude-triaging` to the PR — that label is the
+  routine's "I'm working on this **issue**" signal, not a PR
+  ownership marker.)
+
 - Before pushing:
   - `go build ./...`
   - `go vet ./...`