BAT-009 Design

Schema and persistence design

Reuse manual_assets / asset_snapshots tables from BAT-008 and extend them only additively for write workflow metadata as needed.
manual_assets write lifecycle must support create/update/deactivate without destroying prior snapshot traceability.
asset_snapshots remains append-only; correction runs add new rows/metadata rather than overwriting prior close rows.

Service layer should expose:
- manual asset create/update/deactivate helpers
- snapshot preview helper that returns write-free totals/warnings
- snapshot close helper that materializes authority-source rows for one basis_date
- correction helper/metadata so same-date re-close is represented as a correction append, not overwrite
Close path must preserve source_type, source_id, display name, valuation amount, liquidity_bucket, memo/reason metadata.

server.py should expose mutation MCP tools for manual asset CRUD and snapshot preview/close.
Success/error envelopes must match dcy-007 contract conventions.
Preview responses expose source='live_authority', is_closed_snapshot=false; close responses expose source='snapshot', is_closed_snapshot=true.
Correction close responses must identify that a correction run occurred.

dashboard/app.py should provide manual asset create/edit/deactivate flows and a month-end close panel.
Preview and close actions must be visually distinct.
Screen text should clarify whether displayed values are live authority estimates or closed snapshot values.
Correction history should be explainable at least through summary metadata/messages.