feat(go): chain retained snapshot artifacts

go-agent/README.md

@@ -52,8 +52,8 @@ Current scope:
 - a shared fixture checked against the Python detector by
   `scripts/check-go-parity.py`.
 
-It does not yet provide Python's rich enrichment, assurance chain, notification
-fan-out, or management consumers for those snapshots, and it does not replace
+It does not yet provide Python's full enrichment, notification fan-out, or
+management consumers for those snapshots, and it does not replace
 `enodia-sentinel`. The module requires Go 1.25 or newer; development is currently
 verified with Go 1.26.5. Run a single terminal-visible stateless sweep:
 
@@ -102,7 +102,8 @@ a probe load failure is visible in status events and the polling loop remains
 active. Installing the sidecar does not enable it or alter
 `enodia-sentinel.service`. The unit reaches `active` only after baseline
 initialization, event-log and snapshot-store preflight, and both requested probe
-load attempts finish.
+load attempts finish. Snapshot-store preflight includes the private assurance
+chain.
 
 Alert envelopes are also batched into private
 `alert-YYYYMMDD-HHMMSS.{json,log}` pairs under the same isolated directory.
@@ -115,8 +116,9 @@ the configured `incident_tracking`, `incident_window`, and
 and one snapshot name idempotently. Hot-path enrichment derives bounded
 process/parent context, lineage, remote-IP classification, and candidate paths
 from already-captured data without new I/O. Package ownership, hashes, file
-metadata, integrity anchors, assurance chaining, and notifications remain
-future parity work.
+metadata, richer integrity anchors, and notifications remain future parity
+work. Snapshot text/JSON revisions append synchronized `enodia.hash_chain.v1`
+records to a private local `hash-chain.jsonl`.
 
 After every successfully emitted status record, the service atomically updates
 `/var/lib/enodia-sentinel-go/heartbeat` with the current Unix timestamp (mode