fix: add CodeQL workflow and restrict workflow permissions

- Add custom CodeQL workflow with build-mode: none for java-kotlin
  to fix compilation failure in default setup
- Add explicit permissions (contents: read) to both workflows
  to resolve CodeQL alert #3 (CWE-275)

Author: MO2k4

.github/workflows/codeql.yml

@@ -0,0 +1,49 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+  schedule:
+    - cron: '0 6 * * 1' # Monday 6 AM UTC
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  analyze:
+    name: Analyze (${{ matrix.language }})
+    runs-on: ${{ (matrix.language == 'csharp' && 'windows-latest') || 'ubuntu-latest' }}
+    permissions:
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - language: actions
+            build-mode: none
+          - language: csharp
+            build-mode: none
+          - language: java-kotlin
+            build-mode: none
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: ${{ matrix.build-mode }}
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+        with:
+          category: "/language:${{ matrix.language }}"

.github/workflows/main.yml

@@ -8,6 +8,9 @@ on:
     branches:
       - master
 
+permissions:
+  contents: read
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true