chore(ci): trim Actions spend — drop wasted PR triggers (wave-12.6.7) (#382)

Audit + fix for the Actions budget exhaustion that blocked the wave-12.6
PR cascade. Drops PR triggers from mobile-android (mobile work paused)
and codeql (code-scanning not enabled, PR runs were wasted). See commit
message for full rationale.

Author: Apexone11

.github/workflows/codeql.yml

@@ -12,12 +12,19 @@
 name: "CodeQL Advanced"
 
 on:
+  # CodeQL covers the security-scanning need on every merge to main + a
+  # weekly scheduled scan. Removed the pull_request trigger 2026-05-27 —
+  # the repo doesn't have GitHub code-scanning enabled at the org level
+  # (every PR-time CodeQL run hits "Code scanning is not enabled for
+  # this repository. Please enable code scanning in the repository
+  # settings." and fails), so every PR-time run was wasted Actions
+  # minutes. Re-add the pull_request trigger after enabling code
+  # scanning under Settings → Security.
   push:
     branches: [ "main", "approved-branch" ]
-  pull_request:
-    branches: [ "main", "approved-branch" ]
   schedule:
     - cron: '25 9 * * 4'
+  workflow_dispatch:
 
 jobs:
   analyze:

.github/workflows/mobile-android.yml

@@ -4,18 +4,21 @@ permissions:
   contents: read
 
 on:
+  # Mobile work is paused per CLAUDE.md memory (2026-04-23, files
+  # preserved for resume). Until mobile is unpaused, the Android build
+  # runs only on direct pushes to main + on mobile-v* release tags + on
+  # manual workflow_dispatch. Removed the pull_request trigger 2026-05-27
+  # to stop burning ~10 Actions minutes on every Dependabot frontend
+  # patch (the biggest spender in the budget audit). Re-add the
+  # pull_request trigger when mobile work resumes.
   push:
     branches: ['main']
     tags:
       - 'mobile-v*'
     paths:
       - 'frontend/studyhub-app/**'
       - '.github/workflows/mobile-android.yml'
-  pull_request:
-    branches: ['main']
-    paths:
-      - 'frontend/studyhub-app/**'
-      - '.github/workflows/mobile-android.yml'
+  workflow_dispatch:
 
 jobs:
   build-debug: