ci(codeql): remove workflow in favour of default setup

CodeQL default setup is now enabled via repo settings for go and
python. The workflow-based approach uploaded results as "code quality"
rather than "code scanning", which didn't satisfy the code_scanning
ruleset requirement. Default setup handles this natively.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/codeql.yml

@@ -1,41 +0,0 @@
-name: CodeQL
-
-on:
-  push:
-    branches: [dev, main]
-  pull_request:
-    branches: [dev, main]
-  schedule:
-    - cron: "0 6 * * 1"
-  workflow_dispatch:
-
-jobs:
-  analyze:
-    name: Analyze (${{ matrix.language }})
-    runs-on: ubuntu-latest
-    permissions:
-      actions: read
-      contents: read
-      security-events: write
-
-    strategy:
-      fail-fast: false
-      matrix:
-        language: [go, python]
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v6
-
-      - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4
-        with:
-          languages: ${{ matrix.language }}
-
-      - name: Autobuild
-        uses: github/codeql-action/autobuild@v4
-
-      - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4
-        with:
-          category: "/language:${{ matrix.language }}"