feat: Implement Filesystem and MongoDB provenance writers for PackRun execution context

- Added `FilesystemPackRunProvenanceWriter` to write provenance manifests to the filesystem.
- Introduced `MongoPackRunArtifactReader` to read artifacts from MongoDB.
- Created `MongoPackRunProvenanceWriter` to store provenance manifests in MongoDB.
- Developed unit tests for filesystem and MongoDB provenance writers.
- Established `ITimelineEventStore` and `ITimelineIngestionService` interfaces for timeline event handling.
- Implemented `TimelineIngestionService` to validate and persist timeline events with hashing.
- Created PostgreSQL schema and migration scripts for timeline indexing.
- Added dependency injection support for timeline indexer services.
- Developed tests for timeline ingestion and schema validation.

bench/reachability-benchmark/cases/js/express-eval/src/app.js

@@ -0,0 +1,34 @@
+'use strict';
+
+// Minimal express-like router.
+function makeApp() {
+  const routes = {};
+  return {
+    post(path, handler) {
+      routes[`POST ${path}`] = handler;
+    },
+    handle(method, path, req, res) {
+      const key = `${method} ${path}`;
+      if (routes[key]) {
+        return routes[key](req, res);
+      }
+      return { status: 404, body: 'not found' };
+    }
+  };
+}
+
+function createServer() {
+  const app = makeApp();
+  app.post('/api/admin/exec', (req) => {
+    if (!req || typeof req.body?.code !== 'string') {
+      return { status: 400, body: 'bad request' };
+    }
+    // Sink: eval on admin endpoint (reachable)
+    // eslint-disable-next-line no-eval
+    const result = eval(req.body.code);
+    return { status: 200, body: String(result) };
+  });
+  return app;
+}
+
+module.exports = { createServer };