feat: Add Scanner CI runner and related artifacts

- Implemented `run-scanner-ci.sh` to build and run tests for the Scanner solution with a warmed NuGet cache.
- Created `excititor-vex-traces.json` dashboard for monitoring Excititor VEX observations.
- Added Docker Compose configuration for the OTLP span sink in `docker-compose.spansink.yml`.
- Configured OpenTelemetry collector in `otel-spansink.yaml` to receive and process traces.
- Developed `run-spansink.sh` script to run the OTLP span sink for Excititor traces.
- Introduced `FileSystemRiskBundleObjectStore` for storing risk bundle artifacts in the filesystem.
- Built `RiskBundleBuilder` for creating risk bundles with associated metadata and providers.
- Established `RiskBundleJob` to execute the risk bundle creation and storage process.
- Defined models for risk bundle inputs, entries, and manifests in `RiskBundleModels.cs`.
- Implemented signing functionality for risk bundle manifests with `HmacRiskBundleManifestSigner`.
- Created unit tests for `RiskBundleBuilder`, `RiskBundleJob`, and signing functionality to ensure correctness.
- Added filesystem artifact reader tests to validate manifest parsing and artifact listing.
- Included test manifests for egress scenarios in the task runner tests.
- Developed timeline query service tests to verify tenant and event ID handling.

bench/reachability-benchmark/README.md

@@ -13,6 +13,7 @@ Deterministic, reproducible benchmark for reachability analysis tools.
 - `benchmark/truth/` — ground-truth labels (hidden/internal split optional).
 - `benchmark/submissions/` — sample submissions and format reference.
 - `tools/scorer/` — `rb-score` CLI and tests.
+- `tools/build/` — `build_all.py` (run all cases) and `validate_builds.py` (run twice and compare hashes).
 - `baselines/` — reference runners (Semgrep, CodeQL, Stella) with normalized outputs.
 - `ci/` — deterministic CI workflows and scripts.
 - `website/` — static site (leaderboard/docs/downloads).