docs consolidation work

docs/modules/snapshot/README.md

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+# Snapshot
+
+**Status:** Design/Planning
+**Source:** N/A (cross-cutting concept)
+**Owner:** Platform Team
+
+## Purpose
+
+Snapshot defines the knowledge snapshot model for deterministic, point-in-time captures of StellaOps data. Enables offline operation, merge preview, replay, and air-gap export with cryptographic integrity.
+
+## Components
+
+**Concept Documentation:**
+- `merge-preview.md` - Merge preview specification
+- `replay-yaml.md` - Replay YAML format and semantics
+
+**Snapshot Types:**
+- Advisory snapshots (Concelier ingestion state)
+- VEX snapshots (VexHub distribution state)
+- SBOM snapshots (SbomService repository state)
+- Policy snapshots (Policy Engine rule state)
+- Task pack snapshots (PacksRegistry versions)
+
+## Implementation Locations
+
+Snapshot functionality is implemented across multiple modules:
+- **AirGap** - Snapshot export/import orchestration
+- **ExportCenter** - Snapshot bundle creation
+- **Replay** - Deterministic replay from snapshots
+- **Concelier** - Advisory snapshot merge preview
+- All data modules (snapshot sources)
+
+## Dependencies
+
+- AirGap (snapshot orchestration)
+- ExportCenter (bundle creation)
+- Replay (snapshot replay)
+- All data modules (snapshot sources)
+
+## Related Documentation
+
+- Merge Preview: `./merge-preview.md`
+- Replay YAML: `./replay-yaml.md`
+- AirGap: `../airgap/`
+- ExportCenter: `../export-center/`
+- Replay: `../replay/` (if exists)
+- Offline Kit: `../../24_OFFLINE_KIT.md`
+
+## Current Status
+
+Snapshot concepts documented in merge-preview.md and replay-yaml.md. Implementation distributed across AirGap (export/import), ExportCenter (packaging), and Replay (playback) modules. Used for offline/air-gap operation.