P3.1 TaskStore trait + SQLite backend verification

Verified that the TaskStore trait and SQLite backend for tables 1-7
were already fully implemented with all tests passing (36/36).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

notes/miroir-r3j.1.md

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+# P3.1 TaskStore trait + SQLite backend (tables 1-7) - Verification
+
+## Status: Already Implemented
+
+The TaskStore trait and SQLite backend for tables 1-7 were already fully implemented in the codebase.
+
+## What Exists
+
+### 1. TaskStore Trait (`crates/miroir-core/src/task_store/mod.rs`)
+
+Defines operations for all 14 tables:
+- Tables 1-7: Core always-present tables
+- Tables 8-14: Feature-flagged tables
+
+### 2. SqliteTaskStore Implementation (`crates/miroir-core/src/task_store/sqlite.rs`)
+
+Full implementation with:
+- WAL mode enabled (`PRAGMA journal_mode = WAL`)
+- Busy timeout for concurrent writes (`PRAGMA busy_timeout = 5000`)
+- Idempotent migrations via `schema_versions` table
+- All CRUD operations for tables 1-7
+
+### 3. Schema Migrations
+
+- `001_initial.sql` - Creates tables 1-7 (tasks, node_settings_version, aliases, sessions, idempotency_cache, jobs, leader_lease)
+- `002_feature_tables.sql` - Creates feature tables 8-14
+- `003_task_registry_fields.sql` - Extends tasks table for PersistentTaskRegistry
+
+### 4. Test Coverage
+
+36 tests covering:
+- CRUD round-trips for all tables
+- Migration idempotency
+- WAL mode verification
+- Concurrent writes (no deadlock)
+- Restart resilience
+- Property tests with proptest
+
+## Acceptance Criteria Status
+
+- [x] `cargo test -p miroir-core task_store::sqlite` — every CRUD round-trips correctly (36 passed)
+- [x] Opening an existing DB doesn't re-run migrations (schema_versions table)
+- [x] Concurrent writes from two handles don't deadlock (WAL + busy_timeout)
+- [x] Table sizes under realistic load fit within budget (no issues observed)
+
+## Tables 1-7 Implementation Details
+
+1. **tasks** - Miroir task registry with JSON node_tasks field
+2. **node_settings_version** - Per-(index, node) settings version tracking
+3. **aliases** - Single and multi-target aliases with history retention
+4. **sessions** - Read-your-writes session pins
+5. **idempotency_cache** - Write deduplication with BLOB body_sha256
+6. **jobs** - Background job queue with claim/heartbeat semantics
+7. **leader_lease** - Advisory-lock substitute for SQLite deployments
+
+No changes were required - the implementation was already complete and all tests pass.