feat: add ledger backup safety workflow

confirm dcy-002 and add REQ/BAT evidence

add ledger backup/status metadata workflow

document restore as runbook/script-only guarded operation

add synthetic DB backup/restore smoke tests

docs/batches/bat-002_20260627_operational-safety-backup-restore-validation-db/planning.md

@@ -0,0 +1,34 @@
+# BAT-002 Planning
+
+## Included REQ
+- REQ-002: 운영 안전 백업·복구·검증 DB 워크플로우
+
+## Delivery Plan
+1. Add service helpers for non-sensitive DB status evidence and SQLite online backup creation.
+2. Add additive MCP tools for backup creation, backup list, backup status/hash, and DB status.
+3. Add a non-MCP restore smoke script requiring explicit approval for overwriting an existing target DB.
+4. Add synthetic DB tests for status evidence, backup/list/status/hash, retention, and restore smoke policy.
+5. Update runtime/data/interface docs and add a runbook.
+6. Run targeted/full verification and request jarcaledgerqc QC gate.
+
+## Dependencies
+- Existing SQLite initialization and additive migration behavior in `jarca_ledger_mcp/db.py`.
+- Existing service response convention: `{"success": True, ...}` and `fail(...)` error shape.
+- Synthetic pytest tmp DBs for safe evidence.
+
+## Design Gate
+Design required: yes.
+
+Reason: this batch changes the MCP interface surface and runtime/data safety baseline, and must explicitly preserve restore non-exposure and sensitive evidence restrictions.
+
+## Milestones
+- M1: REQ-002 Approved and BAT-002 scaffolded.
+- M2: Backup/status/list/hash helpers and MCP tools implemented.
+- M3: Restore smoke script and runbook documented without MCP restore surface.
+- M4: Synthetic tests and docs evidence complete.
+- M5: QC gate PASS/PASS_WITH_NOTES, then REQ-002 Implemented.
+
+## Risks
+- Accidentally exposing restore as MCP would violate dcy-002 policy.
+- SQLite WAL copy must be consistent; implementation should use SQLite online backup API rather than raw file copy for backup creation.
+- Evidence must not serialize sensitive row-level details.