ci: add timeout-minutes to all CI jobs (#2148)

A hung unit test on PR #2120 ran for 3+ hours before manual cancellation,
burning ~185 minutes of Actions quota. Add timeouts to cap runaway jobs:
detect-changes (2m), docs-check/lint (5m), build/windows (15m).

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

.github/workflows/ci.yml

@@ -24,6 +24,7 @@ concurrency:
 
 jobs:
   detect-changes:
+    timeout-minutes: 2
     runs-on: ubuntu-latest
     outputs:
       docs-only: ${{ steps.check.outputs.docs-only }}
@@ -59,6 +60,7 @@ jobs:
           fi
 
   docs-check:
+    timeout-minutes: 5
     runs-on: ubuntu-latest
     needs: detect-changes
     steps:
@@ -70,6 +72,7 @@ jobs:
         run: bash scripts/docs-prompt-injection-scan.sh --diff origin/main
 
   lint:
+    timeout-minutes: 5
     needs: detect-changes
     runs-on: ubuntu-latest
     steps:
@@ -96,6 +99,7 @@ jobs:
         run: node scripts/check-skill-references.mjs
 
   build:
+    timeout-minutes: 15
     needs: detect-changes
     if: needs.detect-changes.outputs.docs-only != 'true'
     runs-on: ubuntu-latest
@@ -135,6 +139,7 @@ jobs:
         run: npm run test:integration
 
   windows-portability:
+    timeout-minutes: 15
     needs: detect-changes
     if: >-
       needs.detect-changes.outputs.docs-only != 'true' &&