feat: Add Promotion-Time Attestations for Stella Ops

- Introduced a new document for promotion-time attestations, detailing the purpose, predicate schema, producer workflow, verification flow, APIs, and security considerations.
- Implemented the `stella.ops/promotion@v1` predicate schema to capture promotion evidence including image digest, SBOM/VEX artifacts, and Rekor proof.
- Defined producer responsibilities and workflows for CLI orchestration, signer responsibilities, and Export Center integration.
- Added verification steps for auditors to validate promotion attestations offline.

feat: Create Symbol Manifest v1 Specification

- Developed a specification for Symbol Manifest v1 to provide a deterministic format for publishing debug symbols and source maps.
- Defined the manifest structure, including schema, entries, source maps, toolchain, and provenance.
- Outlined upload and verification processes, resolve APIs, runtime proxy, caching, and offline bundle generation.
- Included security considerations and related tasks for implementation.

chore: Add Ruby Analyzer with Git Sources

- Created a Gemfile and Gemfile.lock for Ruby analyzer with dependencies on git-gem, httparty, and path-gem.
- Implemented main application logic to utilize the defined gems and output their versions.
- Added expected JSON output for the Ruby analyzer to validate the integration of the new gems and their functionalities.
- Developed internal observation classes for Ruby packages, runtime edges, and capabilities, including serialization logic for observations.

test: Add tests for Ruby Analyzer

- Created test fixtures for Ruby analyzer, including Gemfile, Gemfile.lock, main application, and expected JSON output.
- Ensured that the tests validate the correct integration and functionality of the Ruby analyzer with the specified gems.

docs/implplan/SPRINT_163_exportcenter_ii.md

@@ -13,6 +13,7 @@ EXPORT-OBS-51-001 | TODO | Emit metrics for export planner latency, bundle build
 EXPORT-OBS-52-001 | TODO | Publish timeline events for export lifecycle (`export.requested`, `export.built`, `export.distributed`, `export.failed`) embedding manifest hashes and evidence refs. Provide dedupe + retry logic. Dependencies: EXPORT-OBS-51-001. | Exporter Service Guild (src/ExportCenter/StellaOps.ExportCenter)
 EXPORT-OBS-53-001 | TODO | Push export manifests + distribution transcripts to evidence locker bundles, ensuring Merkle root alignment and DSSE pre-sign data available. Dependencies: EXPORT-OBS-52-001. | Exporter Service Guild, Evidence Locker Guild (src/ExportCenter/StellaOps.ExportCenter)
 EXPORT-OBS-54-001 | TODO | Produce DSSE attestations for each export artifact and distribution target, expose verification API `/exports/{id}/attestation`, and integrate with CLI verify path. Dependencies: EXPORT-OBS-53-001. | Exporter Service Guild, Provenance Guild (src/ExportCenter/StellaOps.ExportCenter)
+EXPORT-OBS-54-002 | TODO | Add promotion attestation assembly to export runs (compute SBOM/VEX digests, embed Rekor proofs, bundle DSSE envelopes) and ensure Offline Kit packaging includes the resulting JSON + DSSE envelopes. Dependencies: EXPORT-OBS-54-001, PROV-OBS-53-003. | Exporter Service Guild, Provenance Guild (src/ExportCenter/StellaOps.ExportCenter)
 EXPORT-OBS-55-001 | TODO | Add incident mode enhancements (extra tracing for slow exports, additional debug logs, retention bump). Emit incident activation events to timeline + notifier. Dependencies: EXPORT-OBS-54-001. | Exporter Service Guild, DevOps Guild (src/ExportCenter/StellaOps.ExportCenter)
 EXPORT-RISK-69-001 | TODO | Add Export Center job handler `risk-bundle` with provider selection, manifest signing, and audit logging. | Exporter Service Guild, Risk Bundle Export Guild (src/ExportCenter/StellaOps.ExportCenter)
 EXPORT-RISK-69-002 | TODO | Enable simulation report exports pulling scored data + explainability snapshots. Dependencies: EXPORT-RISK-69-001. | Exporter Service Guild, Risk Engine Guild (src/ExportCenter/StellaOps.ExportCenter)