feat: enforce Copilot code review ruleset via sync script (#9)

## Summary

- Add `sync_rulesets()` function to the sync script that creates and
verifies the Copilot code review ruleset on all repositories
- Add ruleset configuration to `config/baseline.json` (deletion
protection, non-fast-forward, Copilot review)
- Add CodeRabbit manual setup note to README (no API available for
automation)
- Add `rulesets` to baseline schema validation in quality-checks.yml

## Test plan

- [ ] Trigger dry-run workflow to verify ruleset drift detection works
- [ ] Verify existing repos with the ruleset show as compliant
- [ ] Test on a repo without the ruleset to confirm creation works
- [ ] Confirm quality-checks pass with new `rulesets` schema section

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Added Rulesets support to manage branch protection rules and enforce
Copilot code review on the default branch.
* Implemented automatic Copilot code review enforcement through
configurable rulesets.

* **Documentation**
* Updated configuration documentation to detail the new Rulesets feature
and available rules.
* Clarified code review behavior for both Copilot and CodeRabbit,
including manual setup requirements for CodeRabbit.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: gamaware

.github/workflows/quality-checks.yml

@@ -90,7 +90,7 @@ jobs:
       - name: Validate baseline schema
         run: |
           ERRORS=0
-          for section in repo_settings security branch_protection labels required_files; do
+          for section in repo_settings security branch_protection rulesets labels required_files; do
             if ! jq -e ".$section" config/baseline.json > /dev/null 2>&1; then
               echo "ERROR: Missing section '$section' in baseline.json"
               ERRORS=$((ERRORS + 1))

CLAUDE.md

@@ -100,10 +100,11 @@ The sync script (`scripts/sync-repo-settings.sh`) enforces:
    alerts
 3. **Branch protection**: reviews, CODEOWNERS, linear history,
    conversation resolution
-4. **Labels**: standard issue labels across all repos
-5. **Default branch**: ensures all repos use `main`
-6. **Metadata**: flags missing descriptions and topics (advisory)
-7. **Required files**: LICENSE, README, CODEOWNERS, etc.
+4. **Rulesets**: Copilot code review ruleset on default branch
+5. **Labels**: standard issue labels across all repos
+6. **Default branch**: ensures all repos use `main`
+7. **Metadata**: flags missing descriptions and topics (advisory)
+8. **Required files**: LICENSE, README, CODEOWNERS, etc.
 
 Configuration lives in `config/baseline.json` with per-repo
 overrides in `config/overrides.json`.

README.md

@@ -98,6 +98,18 @@ ensures clean `git log` and bisectability.
 | Required conversation resolution | `true` | All comments must be resolved |
 | Enforce admins | `false` | Admins can bypass when needed |
 
+### Rulesets
+
+The Copilot code review ruleset is enforced on every repository's
+default branch. The sync script creates it if missing and verifies
+enforcement is active.
+
+| Rule | Purpose |
+| --- | --- |
+| `deletion` | Prevent branch deletion |
+| `non_fast_forward` | Prevent force pushes |
+| `copilot_code_review` | Require Copilot review on PRs |
+
 ### Labels
 
 Standard labels are created on every repo for consistent issue
@@ -272,8 +284,15 @@ Add repo names to the `excluded` array in `config/overrides.json`:
 
 ## Code Review
 
+- **GitHub Copilot**: auto-review via ruleset (enforced automatically
+  by the sync script)
 - **CodeRabbit**: auto-review on PRs via `.coderabbit.yaml`
-- **GitHub Copilot**: auto-review via ruleset with custom instructions
+
+> **Note:** CodeRabbit must be enabled manually per repository through
+> the [CodeRabbit dashboard](https://app.coderabbit.ai). There is no
+> API to automate this. After installing the GitHub App, select "All
+> repositories" to cover new repos automatically, or add repos
+> individually through the dashboard.
 
 ## CI/CD Pipelines
 

config/baseline.json

@@ -66,6 +66,30 @@
       "description": "New repository discovered"
     }
   ],
+  "rulesets": {
+    "copilot_code_review": {
+      "name": "Copilot review for default branch",
+      "enforcement": "active",
+      "target": "branch",
+      "conditions": {
+        "ref_name": {
+          "include": ["~DEFAULT_BRANCH"],
+          "exclude": []
+        }
+      },
+      "rules": [
+        {"type": "deletion"},
+        {"type": "non_fast_forward"},
+        {
+          "type": "copilot_code_review",
+          "parameters": {
+            "review_on_push": false,
+            "review_draft_pull_requests": false
+          }
+        }
+      ]
+    }
+  },
   "required_files": [
     "LICENSE",
     "README.md",

scripts/sync-repo-settings.sh

@@ -373,6 +373,71 @@ sync_labels() {
     echo -e "$changes"
 }
 
+# Ensure Copilot code review ruleset exists
+sync_rulesets() {
+    local repo="$1"
+    local effective
+    effective=$(get_effective_settings "$repo")
+    local changes=""
+
+    local ruleset_name
+    ruleset_name=$(echo "$effective" | jq -r '.rulesets.copilot_code_review.name // empty')
+    if [ -z "$ruleset_name" ]; then
+        echo ""
+        return
+    fi
+
+    # List rulesets — bail if the API call itself fails
+    local rulesets_json existing
+    if ! rulesets_json=$(gh api "repos/$OWNER/$repo/rulesets" 2>/dev/null); then
+        log "WARN: Could not list rulesets for $repo"
+        echo ""
+        return
+    fi
+    existing=$(echo "$rulesets_json" | jq -r --arg name "$ruleset_name" '.[] | select(.name == $name) | .id' | head -n1)
+
+    local desired_ruleset
+    desired_ruleset=$(echo "$effective" | jq '.rulesets.copilot_code_review')
+
+    if [ -n "$existing" ]; then
+        # Compare full ruleset config, not just enforcement
+        local current_ruleset desired_normalized current_normalized
+        current_ruleset=$(gh api "repos/$OWNER/$repo/rulesets/$existing" 2>/dev/null || echo "")
+        desired_normalized=$(echo "$desired_ruleset" | jq -cS '{name, enforcement, target, conditions, rules}')
+        current_normalized=$(echo "$current_ruleset" | jq -cS '{name, enforcement, target, conditions, rules}')
+        if [ "$current_normalized" != "$desired_normalized" ]; then
+            changes="- Copilot review ruleset: configuration drift detected\n"
+            if [ "$MODE" = "--apply" ]; then
+                if gh api -X PUT "repos/$OWNER/$repo/rulesets/$existing" \
+                    --input <(echo "$desired_ruleset") \
+                    > /dev/null 2>&1; then
+                    log "APPLIED Copilot review ruleset for $repo"
+                else
+                    log "WARN: Could not update ruleset for $repo"
+                fi
+            else
+                log "DRIFT detected in Copilot review ruleset for $repo"
+            fi
+        else
+            log "OK: Copilot review ruleset for $repo"
+        fi
+    else
+        changes="- Copilot review ruleset: **missing** -> will be created\n"
+        if [ "$MODE" = "--apply" ]; then
+            if gh api -X POST "repos/$OWNER/$repo/rulesets" \
+                --input <(echo "$desired_ruleset") \
+                > /dev/null 2>&1; then
+                log "APPLIED Copilot review ruleset for $repo"
+            else
+                log "WARN: Could not create ruleset for $repo"
+            fi
+        else
+            log "DRIFT detected: missing Copilot review ruleset for $repo"
+        fi
+    fi
+    echo -e "$changes"
+}
+
 # Check default branch matches config
 check_default_branch() {
     local repo="$1"
@@ -513,6 +578,13 @@ REPORT_HEADER
             repo_drift="${repo_drift}### Branch Protection\n\n${protection_changes}\n"
         fi
 
+        # Rulesets (Copilot code review)
+        local ruleset_changes
+        ruleset_changes=$(sync_rulesets "$repo")
+        if [ -n "$ruleset_changes" ]; then
+            repo_drift="${repo_drift}### Rulesets\n\n${ruleset_changes}\n"
+        fi
+
         # Labels
         local label_changes
         label_changes=$(sync_labels "$repo")