feat: report store durability status

docs/architecture.md

@@ -10,7 +10,12 @@ The local metadata store is SQLite product state. `geth-store` tracks a numeric
 `schema_version` in the `meta` table and applies ordered migrations up to the
 crate's current schema version when the store opens. Fresh database creation and
 repeated opens are idempotent; migrations that change existing schemas run in a
-SQLite transaction where SQLite supports it.
+SQLite transaction where SQLite supports it. File-backed stores deliberately use
+SQLite WAL mode with `synchronous=NORMAL`: committed transactions remain
+consistent after process crashes, while the most recent transaction can be lost
+on an OS crash or power loss before the WAL is durable. `geth status` reports
+the observed schema version, journal mode, synchronous mode, and whether those
+values match the expected store policy.
 
 Service management is also exposed through the single binary. `geth daemon
 service ...` installs and controls a user-level service definition for the local

docs/production-readiness-roadmap.md

@@ -142,11 +142,11 @@ it.
   - `[ ]` Backup output avoids copying private SSH admin keys.
   - `[ ]` Docs explain what is and is not included.
 
-- `[ ]` Document database durability settings.
+- `[x]` Document database durability settings.
   Acceptance criteria:
-  - `[ ]` WAL and synchronous settings are chosen deliberately.
-  - `[ ]` Crash-recovery expectations are documented.
-  - `[ ]` `geth doctor` or status output reports obvious store issues.
+  - `[x]` WAL and synchronous settings are chosen deliberately.
+  - `[x]` Crash-recovery expectations are documented.
+  - `[x]` `geth doctor` or status output reports obvious store issues.
 
 ## Phase 4: Security Boundary Closure