feat: add ADR TOC check

.github/workflows/adr-check-toc.yaml

@@ -0,0 +1,34 @@
+---
+'on':
+  workflow_call:
+    inputs:
+      jobs_run_on:
+        default: ubuntu-latest
+        description: The runner group on which jobs will run.
+        required: false
+        type: string
+      timeout_minutes:
+        description: The maximum time (in minutes) for a job to run.
+        default: 5
+        required: false
+        type: number
+      working_directory:
+        description: The working directory where all jobs should be executed.
+        default: '.'
+        required: false
+        type: string
+
+jobs:
+  adr-check-toc:
+    defaults:
+      run:
+        working-directory: ${{ inputs.working_directory }}
+    runs-on: ${{ inputs.jobs_run_on }}
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+      - name: Install adr tools
+        run: git clone https://github.com/npryce/adr-tools.git
+      - name: 'Test for uncommitted changes'
+        run: adr-tools/src/adr generate toc | diff README.md -
+    timeout-minutes: ${{ inputs.timeout_minutes }}

README.md

@@ -14,6 +14,14 @@ parameters that can be passed with `with:` from calling repositories:
 * `working_directory`: The working directory where all jobs should be executed.
   Default: `.`
 
+### adr-check-toc.yaml
+
+This workflow will run the `adr generate toc` command using
+[adr](https://github.com/npryce/adr-tools) to generate the Table of Contents for the
+ADRs in the repository. The workflow assumes the output goes to the `README.md` in the
+same directory as the ADRs. This check makes sure PRs haven't forgotten to run this
+command as part of their commits.
+
 ### conventional-commit.yaml
 
 This workflow will run the