Add new features and tests for AirGap and Time modules

- Introduced `SbomService` tasks documentation.
- Updated `StellaOps.sln` to include new projects: `StellaOps.AirGap.Time` and `StellaOps.AirGap.Importer`.
- Added unit tests for `BundleImportPlanner`, `DsseVerifier`, `ImportValidator`, and other components in the `StellaOps.AirGap.Importer.Tests` namespace.
- Implemented `InMemoryBundleRepositories` for testing bundle catalog and item repositories.
- Created `MerkleRootCalculator`, `RootRotationPolicy`, and `TufMetadataValidator` tests.
- Developed `StalenessCalculator` and `TimeAnchorLoader` tests in the `StellaOps.AirGap.Time.Tests` namespace.
- Added `fetch-sbomservice-deps.sh` script for offline dependency fetching.

docs/modules/policy/TASKS.md

@@ -2,5 +2,8 @@
 
 | Task ID | State | Notes |
 | --- | --- | --- |
+| `PREP-EXPORT-CONSOLE-23-001` | DOING (2025-11-20) | Drafted export bundle + scheduler job contract (see `docs/modules/policy/design/export-console-bundle-contract.md`); waiting on DSSE/storage decisions from Console/Scheduler/Authority. |
+| `PREP-POLICY-AIRGAP-56-001` | DOING (2025-11-20) | Drafted mirror bundle schema for air-gap/ sealed mode (see `docs/modules/policy/design/policy-mirror-bundle-schema.md`); waiting on trust-root and retention policy decisions. |
+| `PREP-POLICY-ENGINE-30-001` | DOING (2025-11-20) | Drafted overlay projection contract (see `docs/modules/policy/design/policy-overlay-projection.md`); waiting on 29-004 metrics/log schema from Platform/Observability. |
 | `SCANNER-POLICY-0001` | DONE (2025-11-10) | Ruby component predicates implemented in engine/tests, DSL docs updated, offline kit verifies `seed-data/analyzers/ruby/git-sources`. |
 | `DOCS-AIAI-31-006` | DONE (2025-11-13) | Published `docs/policy/assistant-parameters.md` capturing Advisory AI configuration knobs (inference/guardrails/cache/queue) and linked it from the module architecture dossier. |