fix(ci): target promotion PR for Claude review comments (#2576)

* fix(ci): target promotion PR for Claude review comments

The Claude Code Review workflow runs on staging promotion PRs but the
agent was tracing changes back to original source PRs and posting
comments there (e.g. on already-merged #2539 instead of promotion
#2575). Fix by explicitly passing the promotion PR number in the prompt.

Also tell the agent which tools are available to avoid wasting turns
on permission denials (~24% of turns were denied tool calls).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: resolve CI failures — restore clippy allow, fix install-param extraction

- Restore `#[allow(clippy::too_many_arguments)]` on `register_startup_channels`
  that was accidentally removed
- Add `tool_install`/`tool_activate` parameter name extraction to
  `pending_gate_extension_name` fallback path (mirrors AuthManager logic)
  so extension name resolves correctly without auth_manager

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/claude-review.yml

@@ -82,9 +82,11 @@ jobs:
                timeouts, resource leaks (file handles, connections), large allocations
                in hot paths.
 
-            4. Consolidate all agent findings and post exactly one comment on the PR
-               using `gh pr comment` with this format. If no issues were found,
-               post "No issues found." instead:
+            4. Consolidate all agent findings and post exactly one comment on
+               THIS promotion PR (#${{ github.event.pull_request.number }})
+               using `gh pr comment ${{ github.event.pull_request.number }}`.
+               Do NOT comment on the original source PRs — only on this promotion PR.
+               If no issues were found, post "No issues found." instead:
 
             ### Code review
 
@@ -108,3 +110,6 @@ jobs:
             - Do NOT check build signal or attempt to build/test the code
             - Ignore pre-existing issues not introduced by this PR
             - Ignore issues a linter/compiler would catch (formatting, imports, types)
+            - Your ONLY available tools are: Read, Glob, Grep, Agent, and Bash with
+              gh/git commands. Do NOT attempt cat, cargo, python, curl, or any other
+              Bash commands — they will be denied and waste turns.