feat: deploy jarca ledger network mcp service

- add Docker deployment for independent jarca-ledger container
- enable FastMCP streamable-http runtime configuration
- document dcy-013, REQ-019, and BAT-015 verification evidence
- update structure/runtime baselines and deployment runbook

docs/batches/bat-015_20260707_docker-network-mcp-deployment/implementation.md

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+# BAT-015 Implementation
+
+## Code changes
+
+- `jarca_ledger_mcp/adapters/mcp/server.py`
+  - Added `McpRuntimeConfig` dataclass.
+  - Added env parsing for `JARCA_MCP_TRANSPORT`, `JARCA_MCP_HOST`, `JARCA_MCP_PORT`, `JARCA_MCP_STREAMABLE_HTTP_PATH`, `JARCA_MCP_SSE_PATH`, `JARCA_MCP_MESSAGE_PATH`, `JARCA_MCP_STATELESS_HTTP`.
+  - Instantiates FastMCP with configured host/port/path values.
+  - Calls `mcp.run(transport=_runtime_config.transport)`.
+- `tests/test_mcp_http_runtime.py`
+  - Added config tests for default stdio, streamable-http env, and invalid transport rejection.
+
+## Deployment files
+
+- `Dockerfile`
+  - Builds `jarca-ledger:latest` from `python:3.12-slim`.
+  - Installs `.[dashboard]` dependencies.
+  - Exposes port 8000 and runs `jarca-ledger-mcp`.
+  - Adds TCP healthcheck against `127.0.0.1:${JARCA_MCP_PORT}`.
+- `.dockerignore`
+  - Excludes `.env`, DBs, financial source files, tests/docs/scripts not needed in image, and local artifacts.
+- `docker-compose.yml`
+  - Defines `container_name: jarca-ledger`.
+  - Maps `8000:8000`.
+  - Mounts `/volume1/docker/jarca-ledger/data:/data`.
+  - Sets streamable-http MCP env.
+  - Uses `restart: unless-stopped`.
+
+## Data migration implementation
+
+1. Created a consistent source snapshot inside the old `jarca` container using SQLite backup API.
+2. Copied snapshot to the host temp path.
+3. Backed up the initial empty `jarca-ledger` DB under `/data/backups/pre_migration_empty_20260705152129.sqlite3`.
+4. Stopped `jarca-ledger`, removed WAL/SHM sidecars, copied the snapshot to `/data/ledger.sqlite3`, normalized permissions, and restarted.
+5. Waited for Docker health to become `healthy`.
+
+## Documentation changes
+
+- Added `docs/runbooks/docker-network-mcp-deploy.md`.
+- Added this StagePilot post-implementation trace: dcy-013, REQ-019, BAT-015.
+- Updated `docs/project-structure.md` and `docs/runtime-flows.md` to include Docker/network MCP runtime.