feat: add receive message reconciliation helper

docs/current-status-card.md

@@ -59,7 +59,7 @@ N13/N14/N15 are pre-business validation results. They can help identify UI eleme
 
 ## Current loop
 
-Current loop: `R11 receive-file download preview contract complete`; next R12 receive-message reconciliation helper.
+Current loop: `R12 receive-message reconciliation helper complete`; next R13 business goals smoke.
 
 Active continuous execution plan: `docs/superpowers/plans/2026-07-10-r6f-r14-continuous-execution-plan.md`.
 
@@ -240,8 +240,8 @@ Continuous execution plan R6f-R14 is approved and execution has started:
 - Plan file: `docs/superpowers/plans/2026-07-10-r6f-r14-continuous-execution-plan.md`.
 - Scope: 15 ordered rounds covering send-message connector/gate hardening, send-file preview/idempotency/package, receive-file download preview, receive-message reconciliation, end-to-end business smoke, and release-candidate report.
 - Execution rule after approval: one round at a time, status-card update, verification, commit, push, then continue automatically until an evidence-only blocker requires user action.
-- Last completed round: R11 receive-file download preview contract.
-- Next active round: R12 receive-message reconciliation helper.
+- Last completed round: R12 receive-message reconciliation helper.
+- Next active round: R13 business goals smoke.
 
 R6g send audit and idempotency replay diagnostics is complete:
 
@@ -354,3 +354,13 @@ R11 receive-file download preview contract is complete:
 - Both paths keep `file_contents_read=false`, `file_copied=false`, `real_download_attempted=false`, and `raw_paths_returned=false`; real file copy remains blocked.
 - `scripts\verify-go-mcp.ps1` now asserts `receive_file_download_preview_blocked=true`.
 - Next node: R12 receive-message reconciliation helper.
+
+R12 receive-message reconciliation helper is complete:
+
+- Added `internal/isphere/message_reconciliation.go` and `internal/isphere/message_reconciliation_test.go`.
+- Strong match uses exact non-empty `message_id`; medium match uses same `conversation_id`, same `sender_id`, and timestamp within 3000 ms.
+- Auto merge is recommended only when all records are strong matches with no unmatched or medium-only rows.
+- Added `scripts\verify-receive-source-reconciliation.ps1 -UseFixture`, which outputs sanitized counts/booleans only.
+- Fixture output: `strong_matches=1`, `medium_matches=1`, `unmatched_left=1`, `unmatched_right=1`, `auto_merge_recommended=false`, and `exact_fixture_auto_merge_recommended=true`.
+- Default `isphere_receive_messages` routing is unchanged; `msglib_readonly` remains explicit only.
+- Next node: R13 business goals smoke.

docs/source-discovery/2026-07-10-receive-message-reconciliation-precheck.md

@@ -136,7 +136,7 @@ Reason:
 
 ## Next implementation node
 
-Recommended next business node: **R2 contact/group search quality hardening**.
+Recommended next business node after R12: continue R13/R14 business smoke and release-candidate closure unless new real evidence changes priority.
 
 Reason:
 
@@ -149,3 +149,28 @@ Future receive-specific node after R2/R3:
 - Add a local-only reconciliation helper that compares PacketReader and MsgLib messages by sanitized keys and outputs only match counts, source refs, and mismatch categories.
 - Do not implement pagination until reconciliation proves which source should drive ordering.
 - Do not implement file download until R3 proves message-to-cache/download mapping.
+
+
+## R12 implementation result
+
+R12 added a local-only reconciliation helper:
+
+- `internal/isphere/message_reconciliation.go`
+- `internal/isphere/message_reconciliation_test.go`
+- `scripts/verify-receive-source-reconciliation.ps1`
+
+Fixture verification:
+
+```json
+{"ok":true,"verification":"receive_source_reconciliation","use_fixture":true,"strong_matches":1,"medium_matches":1,"unmatched_left":1,"unmatched_right":1,"auto_merge_recommended":false,"exact_fixture_auto_merge_recommended":true,"raw_message_bodies_returned":false,"raw_rows_returned":false,"file_paths_returned":false,"default_receive_routing_changed":false}
+```
+
+The helper is pure comparison logic: it performs no DB reads, log reads, send, download, hook, injection, or writes.
+
+Current match behavior:
+
+- strong match: exact non-empty `message_id` on both sides;
+- medium match: same `conversation_id`, same `sender_id`, and timestamp within 3000 ms;
+- auto merge is recommended only for complete strong-match coverage with no unmatched or medium-only records.
+
+Decision remains unchanged: default `isphere_receive_messages` routing stays PacketReader/log-backed. `msglib_readonly` remains explicit only.

docs/superpowers/plans/2026-07-10-r6f-r14-continuous-execution-plan.md

@@ -857,19 +857,19 @@ git push gitea main
 - Produces: `func ReconcileMessageSources(left, right []MessageReconciliationCandidate) MessageReconciliationSummary`.
 - Summary fields: `strong_matches`, `medium_matches`, `unmatched_left`, `unmatched_right`, `auto_merge_recommended`.
 
-- [ ] **Step 1: Write reconciliation tests**
+- [x] **Step 1: Write reconciliation tests**
 
 Add `TestReconcileMessageSourcesStrongAndMediumMatches`: same message id is strong; same conversation/sender and timestamp within 3000ms is medium; auto merge remains false until a strong-ratio threshold is met.
 
-- [ ] **Step 2: Implement pure Go helper**
+- [x] **Step 2: Implement pure Go helper**
 
 No DB/log IO in the helper. It only compares sanitized candidates.
 
-- [ ] **Step 3: Add script wrapper**
+- [x] **Step 3: Add script wrapper**
 
 Script runs against fixture JSON first; optional real evidence mode prints counts and booleans only.
 
-- [ ] **Step 4: Verify and commit**
+- [x] **Step 4: Verify and commit**
 
 ```powershell
 git diff --check
@@ -885,6 +885,14 @@ git push gitea main
 
 **Acceptance gate:** 对账能力存在，但默认 receive routing 不改变。
 
+
+**R12 Result:**
+
+- Added pure Go reconciliation helper and tests.
+- Added `scripts/verify-receive-source-reconciliation.ps1 -UseFixture`.
+- Fixture output is sanitized and keeps `default_receive_routing_changed=false`.
+- Default receive routing remains PacketReader/log-backed; no `auto` merge was enabled.
+
 ---
 
 ### R13: End-to-end business goals smoke