ci: modernize the CodeQL workflow

- run on the actual default branch: the workflow only triggered on
  main, but the default branch is dev, so pushes were never analyzed
- bump github/codeql-action from the deprecated v1/v2 to v4 and
  actions/checkout from v2 (node12, disabled by GitHub) to v7
- fix the stale paths-ignore: the generated protos moved from
  app/repositories/ln_impl/protos to app/lightning/impl/protos long
  ago, and exclude them from the analysis itself via the init config
  (trigger-level paths-ignore only affects when the workflow runs)
- also scan the GitHub Actions workflows (language: actions)
- drop the Autobuild step (a no-op for Python) and the template
  boilerplate comments
- allow manual CodeQL runs via workflow_dispatch

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/codeql-analysis.yml

@@ -1,32 +1,23 @@
-# For most projects, this workflow file will not need changing; you simply need
-# to commit it to your repository.
-#
-# You may wish to alter this file to override the set of languages analyzed,
-# or to provide custom queries or build logic.
-#
-# ******** NOTE ********
-# We have attempted to detect the languages in your repository. Please check
-# the `language` matrix defined below to confirm you have the correct set of
-# supported CodeQL languages.
-#
 name: "CodeQL"
 
 on:
   push:
-    branches: [ main ]
+    branches: [dev, main]
     paths-ignore:
-      - "**/app/repositories/ln_impl/protos/*"
+      - "app/lightning/impl/protos/**"
   pull_request:
     # The branches below must be a subset of the branches above
-    branches: [ main ]
+    branches: [dev, main]
     paths-ignore:
-      - "**/app/repositories/ln_impl/protos/*"
+      - "app/lightning/impl/protos/**"
   schedule:
-    - cron: '20 11 * * 4'
+    - cron: "20 11 * * 4"
+  # allow triggering manually from the Actions tab / gh workflow run
+  workflow_dispatch:
 
 jobs:
   analyze:
-    name: Analyze
+    name: Analyze (${{ matrix.language }})
     runs-on: ubuntu-latest
     permissions:
       actions: read
@@ -36,40 +27,23 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        language: [ 'python' ]
-        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python' ]
-        # Learn more:
-        # https://docs.github.com/en/free-pro-team@latest/github/finding-security-vulnerabilities-and-errors-in-your-code/configuring-code-scanning#changing-the-languages-that-are-analyzed
+        # 'actions' scans the GitHub Actions workflows themselves
+        language: ["python", "actions"]
 
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v2
+      - name: Checkout repository
+        uses: actions/checkout@v7
 
-    # Initializes the CodeQL tools for scanning.
-    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v1
-      with:
-        languages: ${{ matrix.language }}
-        # If you wish to specify custom queries, you can do so here or in a config file.
-        # By default, queries listed here will override any specified in a config file.
-        # Prefix the list here with "+" to use these queries and those in the config file.
-        # queries: ./path/to/local/query, your-org/your-repo/queries@main
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v4
+        with:
+          languages: ${{ matrix.language }}
+          # exclude generated protobuf code from analysis
+          config: |
+            paths-ignore:
+              - app/lightning/impl/protos
 
-    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
-    # If this step fails, then you should remove it and run the build manually (see below)
-    - name: Autobuild
-      uses: github/codeql-action/autobuild@v1
-
-    # ℹ️ Command-line programs to run using the OS shell.
-    # 📚 https://git.io/JvXDl
-
-    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
-    #    and modify them (or add more) to build your code if your project
-    #    uses a compiled language
-
-    #- run: |
-    #   make bootstrap
-    #   make release
-
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v1
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v4
+        with:
+          category: "/language:${{ matrix.language }}"