docs(localdb): phase-2 recon findings

Answers Task 0 with file:line citations against master 2e46d054.

The STOP condition does not fire: PayloadJson is TEXT, no BLOB column, so
alarm_sf_events can be registered for replication as-is.

Two findings reshape the plan's assumptions:

- The drain worker is not a hosted service or an actor. It is a
  self-rescheduling Timer owned by the sink and started from the DI
  factory, so the Primary gate has to live inside DrainOnceAsync as an
  injected delegate -- Core.AlarmHistorian cannot reference
  PrimaryGatePolicy, which lives in Runtime.

- A Primary gate already exists on the enqueue side
  (HistorianAdapterActor.ShouldHistorize), using a different policy than
  the one the plan specifies for the drain. That gate is why today's
  ungated drain is safe: the Secondary never enqueues, so its queue is
  empty. Replicating the table breaks that invariant, which makes the
  drain gate mandatory in the same commit rather than a refinement.

Records deviations D-1 (deterministic content-hash ids so a boot-window
double-enqueue converges instead of duplicating), D-2 (gate denial must be
observable or a snapshot identity mismatch silently stops alarm history),
D-3 (Tasks 2+3 land as one commit) and D-4 (the rig will dead-letter in
~5 minutes at MaxAttempts 10 with no gateway).

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW

docs/plans/2026-07-20-localdb-adoption-phase2.md.tasks.json

@@ -1,15 +1,78 @@
 {
   "planPath": "docs/plans/2026-07-20-localdb-adoption-phase2.md",
   "tasks": [
-    { "id": 0, "subject": "Task 0: Recon — sink schema, seam, drain lifecycle, role-view bridge (STOP conditions)", "status": "pending" },
-    { "id": 1, "subject": "Task 1: alarm_sf_events schema + registration (+ exact-set pin update)", "status": "pending", "blockedBy": [0] },
-    { "id": 2, "subject": "Task 2: Rewire sink onto ILocalDb + delete bespoke file management (cutover 1/2)", "status": "pending", "blockedBy": [1] },
-    { "id": 3, "subject": "Task 3: Primary-gated drain via PrimaryGatePolicy (cutover 2/2 — may co-commit with Task 2)", "status": "pending", "blockedBy": [2] },
-    { "id": 4, "subject": "Task 4: One-time alarm-historian.db legacy migrator", "status": "pending", "blockedBy": [3] },
-    { "id": 5, "subject": "Task 5: Convergence + failover scenarios in the pair harness (+ positive control)", "status": "pending", "blockedBy": [3] },
-    { "id": 6, "subject": "Task 6: Rig config + docs", "status": "pending", "blockedBy": [3] },
-    { "id": 7, "subject": "Task 7: DoD sweep (offline) — STOP and report after this", "status": "pending", "blockedBy": [4, 5, 6] },
-    { "id": 8, "subject": "Task 8: Live gate on the docker-dev rig (needs explicit user go-ahead)", "status": "pending", "blockedBy": [7] }
+    {
+      "id": 0,
+      "subject": "Task 0: Recon \u2014 sink schema, seam, drain lifecycle, role-view bridge (STOP conditions)",
+      "status": "completed",
+      "note": "STOP condition does NOT fire (no BLOB; PayloadJson TEXT). Recon doc: docs/plans/2026-07-20-localdb-phase2-recon.md. Key finding: the drain worker is an internal Timer inside the sink (not a hosted service/actor), so the gate is a Func<bool> ctor param; and HistorianAdapterActor already primary-gates ENQUEUE with a different policy (ShouldHistorize) - which is why today's ungated drain is safe and why replication breaks it. Deviations D-1..D-4 recorded."
+    },
+    {
+      "id": 1,
+      "subject": "Task 1: alarm_sf_events schema + registration (+ exact-set pin update)",
+      "status": "pending",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 2,
+      "subject": "Task 2: Rewire sink onto ILocalDb + delete bespoke file management (cutover 1/2)",
+      "status": "pending",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "Task 3: Primary-gated drain via PrimaryGatePolicy (cutover 2/2 \u2014 may co-commit with Task 2)",
+      "status": "pending",
+      "blockedBy": [
+        2
+      ]
+    },
+    {
+      "id": 4,
+      "subject": "Task 4: One-time alarm-historian.db legacy migrator",
+      "status": "pending",
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "Task 5: Convergence + failover scenarios in the pair harness (+ positive control)",
+      "status": "pending",
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "Task 6: Rig config + docs",
+      "status": "pending",
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "Task 7: DoD sweep (offline) \u2014 STOP and report after this",
+      "status": "pending",
+      "blockedBy": [
+        4,
+        5,
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "subject": "Task 8: Live gate on the docker-dev rig (needs explicit user go-ahead)",
+      "status": "pending",
+      "blockedBy": [
+        7
+      ]
+    }
   ],
-  "lastUpdated": "2026-07-20T00:00:00Z"
+  "lastUpdated": "2026-07-21T00:00:00Z"
 }