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/attestor/replay-prep.md

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+# Attestor Replay Prep — PREP-ATTEST-REPLAY-187-003 (Draft)
+
+Status: Draft (2025-11-20)
+Owners: Attestor Guild
+Scope: Capture prerequisites for wiring Attestor/Rekor anchoring to replay manifests once scanner record payloads are available.
+
+## Expected inputs
+- Replay record schema v1 (from `docs/modules/evidence-locker/replay-payload-contract.md`).
+- Evidence Locker bundle location/pointer for replay artefacts.
+
+## Attestation plan
+- DSSE envelope type: `stella.replay.manifest` (draft).
+- Payload fields: `{record_id, bundle_sha256, policy_run_id?, timestamp}`; signer: Attestor service key; optional Rekor entry when online.
+- Verification endpoint proposal: `POST /attestations/replay/verify` accepting bundle pointer + DSSE; returns chain-of-custody summary.
+
+## Open dependencies
+- Final replay record schema and bundle pointer format.
+- Authority policy on signer identity and Rekor usage in air-gap.
+
+## Handoff
+Use this note to unblock PREP-ATTEST-REPLAY-187-003; update when scanner payloads and Authority decisions land.