fix(comment-checker): add 30s hard timeout to CLI spawn

If the comment-checker binary hangs, Promise.race with a 30s timeout
kills the process and returns a safe fallback {hasComments: false}.

src/hooks/comment-checker/cli.ts

@@ -164,6 +164,8 @@ export async function runCommentChecker(input: HookInput, cliPath?: string, cust
   const jsonInput = JSON.stringify(input)
   debugLog("running comment-checker with input:", jsonInput.substring(0, 200))
 
+  let didTimeout = false
+
   try {
     const args = [binaryPath, "check"]
     if (customPrompt) {
@@ -176,13 +178,39 @@ export async function runCommentChecker(input: HookInput, cliPath?: string, cust
       stderr: "pipe",
     })
 
+    let timeoutId: ReturnType<typeof setTimeout> | null = null
+    const timeoutPromise = new Promise<"timeout">(resolve => {
+      timeoutId = setTimeout(() => {
+        didTimeout = true
+        debugLog("comment-checker timed out after 30s; killing process")
+        try {
+          proc.kill()
+        } catch (err) {
+          debugLog("failed to kill comment-checker process:", err)
+        }
+        resolve("timeout")
+      }, 30_000)
+    })
+
+    try {
       // Write JSON to stdin
       proc.stdin.write(jsonInput)
       proc.stdin.end()
 
-    const stdout = await new Response(proc.stdout).text()
+      const stdoutPromise = new Response(proc.stdout).text()
-    const stderr = await new Response(proc.stderr).text()
+      const stderrPromise = new Response(proc.stderr).text()
-    const exitCode = await proc.exited
+      const exitCodePromise = proc.exited
+
+      const raceResult = await Promise.race([
+        Promise.all([stdoutPromise, stderrPromise, exitCodePromise] as const),
+        timeoutPromise,
+      ])
+
+      if (raceResult === "timeout") {
+        return { hasComments: false, message: "" }
+      }
+
+      const [stdout, stderr, exitCode] = raceResult
 
       debugLog("exit code:", exitCode, "stdout length:", stdout.length, "stderr length:", stderr.length)
 
@@ -198,7 +226,15 @@ export async function runCommentChecker(input: HookInput, cliPath?: string, cust
       // Error case
       debugLog("unexpected exit code:", exitCode, "stderr:", stderr)
       return { hasComments: false, message: "" }
+    } finally {
+      if (timeoutId !== null) {
+        clearTimeout(timeoutId)
+      }
+    }
   } catch (err) {
+    if (didTimeout) {
+      return { hasComments: false, message: "" }
+    }
     debugLog("failed to run comment-checker:", err)
     return { hasComments: false, message: "" }
   }