fix(hook): forward approve feedback to Claude Code agent via systemMessage

[mangxy]

Summary

Fixes #1359

On the Claude Code approve path, annotations collected in the review UI are silently dropped — only the allow decision (with updatedInput / updatedPermissions) reaches the agent. The Gemini CLI approve path already forwards feedback via systemMessage; the Claude Code path does not, so "annotate + approve" is indistinguishable from a plain approve.

Change

One line in apps/hook/server/index.ts: attach the collected feedback as hookSpecificOutput.systemMessage on the approve branch, mirroring the Gemini CLI path (line 2308).

hookSpecificOutput: {
  hookEventName: "PermissionRequest",
  systemMessage: result.feedback || undefined,
  decision: {
    behavior: "allow",
    // ... existing updatedInput / updatedPermissions untouched
  },
},

JSON.stringify drops the field entirely when there is no feedback, so plain approves produce byte-identical output to before.

Verification

• Verified the bug is still present on current main (9f9ee27) before patching.
• Approve with annotations: feedback now delivered to the agent.
• Approve without annotations: output identical to pre-patch (field omitted).
• Deny path unchanged (already delivers feedback via decision.message).