Priced balance categories now carry an explicit `asset_type`
('stock' | 'crypto') so PriceFetchControl can route to the right
provider without symbol heuristics. ETH = Ethan Allen NYSE AND
Ethereum crypto are no longer ambiguous.
Migration v10 adds a nullable column and backfills the two seeded
priced categories (key='stock','crypto'). Legacy custom priced rows
stay NULL until the user edits the category — SnapshotLineRow hides
the price-fetch button when asset_type is NULL on a priced row, so
manual entry remains available.
Service-side validation rejects priced creation without asset_type
('asset_type_required') and rejects values outside ('stock','crypto')
('asset_type_invalid'). Simple kind coerces asset_type to NULL.
The CategoryVariant of AccountForm shows the selector only when
kind=priced, requires it on submit, and resets it on kind switch.
i18n keys added under balance.category.assetType.* (FR + EN).
Tests:
- 4 new Rust migration tests in lib.rs (column add, seed backfill,
legacy row stays NULL, CHECK rejects 'gold')
- 6 new vitest cases on createBalanceCategory + listBalanceAccounts
asserts c.asset_type AS category_asset_type in the join
- balance-flow integration test updated to pass asset_type='stock'
No new test for SnapshotLineRow render guard — project lacks
@testing-library/react + jsdom; the guard is one boolean expression
covered by manual QA per autopilot decisions in PR #167.
Fixes#169
