Adds Category (+ CategoryBillSummary) to @/types and wires categories/
createCategory/updateCategory. Category has no money field of its own (budgets
live on the spending endpoints); the nested per-bill total_paid is a raw SQL sum,
so it's deliberately left unbranded. With categories now typed, useSpending
Categories drops its `any` cast and dead d.categories branch.
Category, Bill, Payment, and the Tracker envelope are the cross-cutting types
used by many components — worth defining upfront. The remaining single-consumer
page responses (summary, analytics, spending, snowball, subscriptions, bank
ledger) are typed alongside their page conversions in phase B, where the exact
fields consumed are visible (more accurate than a speculative interface).
typecheck 0, build green, 48 client tests.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
4af738f947