feat: Implement Scheduler Worker Options and Planner Loop

- Added `SchedulerWorkerOptions` class to encapsulate configuration for the scheduler worker.
- Introduced `PlannerBackgroundService` to manage the planner loop, fetching and processing planning runs.
- Created `PlannerExecutionService` to handle the execution logic for planning runs, including impact targeting and run persistence.
- Developed `PlannerExecutionResult` and `PlannerExecutionStatus` to standardize execution outcomes.
- Implemented validation logic within `SchedulerWorkerOptions` to ensure proper configuration.
- Added documentation for the planner loop and impact targeting features.
- Established health check endpoints and authentication mechanisms for the Signals service.
- Created unit tests for the Signals API to ensure proper functionality and response handling.
- Configured options for authority integration and fallback authentication methods.

.gitea/workflows/build-test-deploy.yml

@@ -109,6 +109,89 @@ jobs:
           if-no-files-found: error
           retention-days: 14
 
+      - name: Export policy run schemas
+        id: export-policy-schemas
+        run: |
+          set -euo pipefail
+          OUTPUT_DIR="artifacts/policy-schemas/${GITHUB_SHA}"
+          mkdir -p "$OUTPUT_DIR"
+          scripts/export-policy-schemas.sh "$OUTPUT_DIR"
+
+      - name: Detect policy schema changes
+        id: detect-policy-schema-changes
+        run: |
+          set -euo pipefail
+          OUTPUT_DIR="artifacts/policy-schemas/${GITHUB_SHA}"
+          FILES=("policy-run-request.schema.json" "policy-run-status.schema.json" "policy-diff-summary.schema.json" "policy-explain-trace.schema.json")
+          CHANGED=()
+          DIFF_FILE="$OUTPUT_DIR/policy-schema-diff.patch"
+          rm -f "$DIFF_FILE"
+
+          for file in "${FILES[@]}"; do
+            if [ ! -f "$OUTPUT_DIR/$file" ]; then
+              echo "Missing exported schema: $OUTPUT_DIR/$file" >&2
+              exit 1
+            fi
+
+            if ! cmp -s "docs/schemas/$file" "$OUTPUT_DIR/$file"; then
+              CHANGED+=("$file")
+              {
+                diff -u "docs/schemas/$file" "$OUTPUT_DIR/$file" || true
+              } >> "$DIFF_FILE"
+              printf '\n' >> "$DIFF_FILE"
+            fi
+          done
+
+          if [ ${#CHANGED[@]} -eq 0 ]; then
+            echo "changed=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          JOINED="$(IFS=', '; echo "${CHANGED[*]}")"
+          echo "changed=true" >> "$GITHUB_OUTPUT"
+          echo "changed_files=$JOINED" >> "$GITHUB_OUTPUT"
+          echo "diff_path=artifacts/policy-schemas/${GITHUB_SHA}/policy-schema-diff.patch" >> "$GITHUB_OUTPUT"
+
+      - name: Upload policy schema artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: policy-schema-exports
+          path: artifacts/policy-schemas
+          if-no-files-found: error
+          retention-days: 14
+
+      - name: Notify policy schema changes
+        if: steps.detect-policy-schema-changes.outputs.changed == 'true'
+        env:
+          SLACK_WEBHOOK: ${{ secrets.POLICY_ENGINE_SCHEMA_WEBHOOK || vars.POLICY_ENGINE_SCHEMA_WEBHOOK }}
+          CHANGED_FILES: ${{ steps.detect-policy-schema-changes.outputs.changed_files }}
+        run: |
+          if [ -z "${SLACK_WEBHOOK:-}" ]; then
+            echo "ℹ️ POLICY_ENGINE_SCHEMA_WEBHOOK not configured; skipping Slack notification."
+            exit 0
+          fi
+
+          payload="$(python3 - <<'PY'
+import json
+import os
+
+changed_files = os.environ.get("CHANGED_FILES", "").strip()
+repo = os.environ["GITHUB_REPOSITORY"]
+sha = os.environ["GITHUB_SHA"]
+commit_url = f"{os.environ['GITHUB_SERVER_URL']}/{repo}/commit/{sha}"
+run_url = f"{os.environ['GITHUB_SERVER_URL']}/{repo}/actions/runs/{os.environ['GITHUB_RUN_ID']}"
+lines = [
+    ":scroll: Policy schema export updated.",
+    f"*Commit:* <{commit_url}|{sha[:7]}>",
+]
+if changed_files:
+    lines.append(f"*Files:* {changed_files}")
+lines.append(f"*CI run:* <{run_url}|Artifacts & diff>")
+print(json.dumps({"text": "\n".join(lines)}))
+PY
+)"
+
+          curl -sSf -X POST -H 'Content-type: application/json' --data "$payload" "$SLACK_WEBHOOK"
       - name: Run release tooling tests
         run: python ops/devops/release/test_verify_release.py