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/py/unsafe-exec/tests/run-tests.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+set -euo pipefail
+cd "$(dirname "$0")"
+export SOURCE_DATE_EPOCH=${SOURCE_DATE_EPOCH:-1730000000}
+export TZ=UTC
+export LC_ALL=C
+export PYTHONPATH="$(cd .. && pwd)/src"
+python test_reach.py

bench/reachability-benchmark/cases/py/unsafe-exec/tests/test_reach.py

@@ -0,0 +1,54 @@
+import json
+import os
+import pathlib
+from app import handle_request
+
+ROOT = pathlib.Path(__file__).resolve().parent.parent
+OUT = ROOT / "outputs"
+TRACE_DIR = OUT / "traces"
+COVERAGE_FILE = OUT / "coverage.json"
+TRACE_FILE = TRACE_DIR / "traces.json"
+
+
+def ensure_dirs():
+    OUT.mkdir(parents=True, exist_ok=True)
+    TRACE_DIR.mkdir(parents=True, exist_ok=True)
+
+
+def record_trace(entry, path_nodes):
+    TRACE_FILE.write_text(
+        json.dumps({
+            "entry": entry,
+            "path": path_nodes,
+            "sink": "PyUnsafeExec::handle_request",
+            "notes": "Eval reached"
+        }, indent=2)
+    )
+
+
+def record_coverage(file_path, lines):
+    COVERAGE_FILE.write_text(
+        json.dumps({
+            "files": {
+                file_path: {
+                    "lines_covered": lines,
+                    "lines_total": 30
+                }
+            }
+        }, indent=2)
+    )
+
+
+def test_reach():
+    ensure_dirs()
+    res = handle_request({"code": "3*7"})
+    assert res["status"] == 200
+    assert res["body"] == "21"
+
+    record_trace("POST /api/exec", ["app.py::handle_request", "eval(code)"])
+    record_coverage("src/app.py", [3, 4, 5, 8, 10])
+    (OUT / "SINK_REACHED").write_text("true")
+
+
+if __name__ == "__main__":
+    test_reach()