refactor(ts): type the spending API responses (Track C)

Promoted SpendingPage's local shapes into @/types (SpendingCategoryEntry,
SpendingSummary, SpendingTransaction(s), SpendingIncome*, SpendingRule,
CategoryGroup, CopyBudgetsResponse) and wired the /spending/* + category-
groups endpoints with get<T>/post<T>. Hooks return typed data; 6 casts
removed; 2 orphaned type aliases dropped. typecheck/lint/build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

HISTORY.md

@@ -3,6 +3,7 @@
 
 ### 🔌 API response typing cleanup (Track C) — promoting page shapes into `@/types`, endpoint by endpoint
 
+- **[Client] Spending domain typed.** Promoted `SpendingPage`'s local response interfaces into `@/types` (`SpendingCategoryEntry`, `SpendingSummary`, `SpendingTransaction`/`…Response`, `SpendingIncomeTx`/`…Response`, `SpendingRule`, `CategoryGroup`, `CopyBudgetsResponse`) and wired `spendingSummary`/`spendingTransactions`/`spendingIncome`/`spendingCategoryRules`/`copySpendingBudgets`/`categoryGroups` with `get<T>`/`post<T>`. `useSpendingSummary`/`useSpendingTransactions`/`useCategoryGroups` now return typed data; the 6 spending `as {…}` casts are gone. Removed 2 now-unused type aliases the cast-removal orphaned (Track E).
 - **[Client] Bank-ledger domain typed end-to-end.** Promoted the `BankTransactionsPage` local interfaces (`Tx`/`Account`/`Ledger`/`LedgerSummary`/`CategoryBreakdown`/auto-categorize preview) into `@/types` as `BankLedgerTransaction` (extends the existing `BankTransaction`, so raw amounts stay branded `Cents`), `BankAccount`, `BankLedger`, `BankLedgerSummary`, `BankCategoryBreakdown`, `AutoCategorizePreview`. Wired the endpoints in `api.ts` (`bankTransactionsLedger` → `get<BankLedger>`, `matchTransaction`/`unmatchTransaction` → `{ transaction }`, `ignoreTransaction`/`unignoreTransaction` → the transaction, `applyTransactionMerchantMatch`/`autoCategorizeTransactions` → their result shapes), so `useBankLedger`'s `data` is now typed and **all 9 `as {…}` casts in the page are gone** — a server field rename now fails in `@/types`, not silently at 9 call sites. Dropped a now-dead `Cents` import (Track E). typecheck/lint/build clean.
 
 ### 🧮 Cross-surface money reconciliation harness (Track B) — pins "same number, same truth"

client/api.ts

@@ -1,6 +1,8 @@
 import type {
   Bill, Category, Payment, TrackerResponse,
   BankLedger, BankLedgerTransaction, AutoCategorizePreview,
+  SpendingSummary, SpendingTransactionsResponse, SpendingIncomeResponse,
+  SpendingRule, CopyBudgetsResponse, CategoryGroup,
 } from '@/types';
 
 // Fetch CSRF token from the server once and cache in memory.
@@ -114,14 +116,14 @@ export const api = {
   acknowledgeVersion:  ()         => post('/auth/acknowledge-version'),
   loginHistory:        ()         => get('/auth/login-history'),
   // Spending
-  spendingSummary:     (p?: QueryParams) => get('/spending/summary', p),
+  spendingSummary:     (p?: QueryParams) => get<SpendingSummary>('/spending/summary', p),
-  spendingTransactions:(p?: QueryParams) => get('/spending/transactions', p),
+  spendingTransactions:(p?: QueryParams) => get<SpendingTransactionsResponse>('/spending/transactions', p),
   categorizeTransaction: (id: Id, d: Body) => patch(`/spending/transactions/${id}/category`, d),
   spendingBudgets:     (p?: QueryParams) => get('/spending/budgets', p),
   setSpendingBudget:   (d: Body)  => put('/spending/budgets', d),
-  copySpendingBudgets: (d: Body)  => post('/spending/budgets/copy', d),
+  copySpendingBudgets: (d: Body)  => post<CopyBudgetsResponse>('/spending/budgets/copy', d),
-  spendingIncome:      (p?: QueryParams) => get('/spending/income', p),
+  spendingIncome:      (p?: QueryParams) => get<SpendingIncomeResponse>('/spending/income', p),
-  spendingCategoryRules: ()       => get('/spending/category-rules'),
+  spendingCategoryRules: ()       => get<{ rules?: SpendingRule[] }>('/spending/category-rules'),
   addSpendingRule:     (d: Body)  => post('/spending/category-rules', d),
   deleteSpendingRule:  (id: Id)   => del(`/spending/category-rules/${id}`),
 
@@ -344,7 +346,7 @@ export const api = {
   restoreCategory:    (id: Id)    => post(`/categories/${id}/restore`),
 
   // Category groups
-  categoryGroups:       ()          => get('/categories/groups'),
+  categoryGroups:       ()          => get<CategoryGroup[]>('/categories/groups'),
   createCategoryGroup:  (data: Body) => post('/categories/groups', data),
   updateCategoryGroup:  (id: Id, data: Body) => put(`/categories/groups/${id}`, data),
   deleteCategoryGroup:  (id: Id)    => del(`/categories/groups/${id}`),

client/pages/SpendingPage.tsx

@@ -20,7 +20,16 @@ import {
 import { CategoryPicker } from '@/components/transactions/CategoryPicker';
 import { formatUSD, asDollars } from '@/lib/money';
 import { errMessage } from '@/lib/utils';
-import type { Category } from '@/types';
+import type {
+  Category,
+  SpendingCategoryEntry as CatEntry,
+  SpendingSummary,
+  SpendingTransaction as SpendingTx,
+  SpendingTransactionsResponse as SpendingTxResponse,
+  SpendingIncomeTx as IncomeTx,
+  SpendingRule,
+  CategoryGroup,
+} from '@/types';
 
 const MONTH_NAMES = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'];
 
@@ -35,43 +44,8 @@ function settingEnabled(value: unknown, fallback = true): boolean {
 
 type Level = 'over' | 'warn' | 'ok';
 
-interface CatEntry {
-  category_id: number | 'other' | null;
-  category_name?: string;
-  amount: number;
-  budget?: number | null;
-  tx_count?: number;
-  avg_3mo?: number;
-  group_id?: number | null;
-}
 type RealCatEntry = CatEntry & { category_id: number };
 
-interface SpendingSummary {
-  by_category?: CatEntry[];
-  total_spending?: number;
-  income?: number;
-  uncategorized_amount?: number;
-  uncategorized_count?: number;
-}
-
-interface SpendingTx {
-  id: number;
-  payee?: string | null;
-  date?: string | null;
-  amount: number;
-  spending_category_id?: number | string | null;
-  spending_category_name?: string | null;
-  [key: string]: unknown;
-}
-interface SpendingTxResponse { transactions?: SpendingTx[]; total?: number; pages?: number }
-
-interface IncomeTx { id: number; payee?: string | null; date?: string | null; amount: number }
-interface IncomeResponse { transactions?: IncomeTx[]; total?: number; pages?: number }
-
-interface SpendingRule { id: number; merchant: string; category_name?: string; category_id?: number }
-interface CategoryGroup { id: number; name: string }
-interface CopyBudgetsResponse { copied: number; budgets?: { category_id: number; amount: number }[] }
-
 type Budgets = Record<string, number | null>;
 
 // pctBar() returns a progress-bar percent plus a YNAB-style status level:
@@ -232,7 +206,7 @@ function IncomeSection({ year, month, totalIncome }: { year: number; month: numb
   const load = useCallback(async (p = 1) => {
     setLoading(true);
     try {
-      const d = await api.spendingIncome({ year, month, page: p }) as IncomeResponse;
+      const d = await api.spendingIncome({ year, month, page: p });
       setRows(d.transactions || []);
       setPages(d.pages || 1);
       setPage(p);
@@ -315,7 +289,7 @@ function RulesManager({ categories }: { categories: Category[] }) {
 
   const load = useCallback(async () => {
     setLoading(true);
-    try { setRules(((await api.spendingCategoryRules()) as { rules?: SpendingRule[] }).rules || []); }
+    try { setRules((await api.spendingCategoryRules()).rules || []); }
     catch { toast.error('Failed to load rules'); }
     finally { setLoading(false); }
   }, []);
@@ -693,15 +667,15 @@ export default function SpendingPage() {
   const [txPage,       setTxPage]       = useState(1);
   const [activeCat,    setActiveCat]    = useState<number | null | undefined>(undefined); // undefined = all
   const { data: summaryRaw = null, isPending: loading, error: summaryErrObj } = useSpendingSummary(year, month);
-  const summary = summaryRaw as SpendingSummary | null;
+  const summary = summaryRaw;
   const { data: txDataRaw, isFetching: txLoading, error: txErrObj } = useSpendingTransactions({ year, month, activeCat, page: txPage });
-  const txData = txDataRaw as SpendingTxResponse | undefined;
+  const txData = txDataRaw;
   const transactions = useMemo(() => txData?.transactions || [], [txData]);
   const txTotal = txData?.total || 0;
   const txPages = txData?.pages || 1;
   const { data: categories = [], error: catErrObj } = useSpendingCategories();
   const { data: categoryGroupsRaw = [] } = useCategoryGroups();
-  const categoryGroups = categoryGroupsRaw as CategoryGroup[];
+  const categoryGroups = categoryGroupsRaw;
   const summaryError = summaryErrObj ? (summaryErrObj.message || 'Failed to load spending summary') : null;
   const txError = txErrObj ? (txErrObj.message || 'Failed to load transactions') : null;
   const catError = catErrObj ? (catErrObj.message || 'Failed to load categories') : null;
@@ -769,7 +743,7 @@ export default function SpendingPage() {
   const handleCopyBudgets = async () => {
     setCopying(true);
     try {
-      const d = await api.copySpendingBudgets({ year, month }) as CopyBudgetsResponse;
+      const d = await api.copySpendingBudgets({ year, month });
       if (d.copied === 0) {
         toast.info('No budgets found in the previous month to copy.');
       } else {

client/types.ts

@@ -88,6 +88,40 @@ export interface AutoCategorizePreview {
   categories?: { name: string; count?: number }[];
 }
 
+// The spending page (GET /spending/*). Amounts are dollars (server fromCents);
+// kept as plain `number` because the page works in numbers via a local formatter.
+export interface SpendingCategoryEntry {
+  category_id: number | 'other' | null;
+  category_name?: string;
+  amount: number;
+  budget?: number | null;
+  tx_count?: number;
+  avg_3mo?: number;
+  group_id?: number | null;
+}
+export interface SpendingSummary {
+  by_category?: SpendingCategoryEntry[];
+  total_spending?: number;
+  income?: number;
+  uncategorized_amount?: number;
+  uncategorized_count?: number;
+}
+export interface SpendingTransaction {
+  id: number;
+  payee?: string | null;
+  date?: string | null;
+  amount: number;
+  spending_category_id?: number | string | null;
+  spending_category_name?: string | null;
+  [key: string]: unknown;
+}
+export interface SpendingTransactionsResponse { transactions?: SpendingTransaction[]; total?: number; pages?: number }
+export interface SpendingIncomeTx { id: number; payee?: string | null; date?: string | null; amount: number }
+export interface SpendingIncomeResponse { transactions?: SpendingIncomeTx[]; total?: number; pages?: number }
+export interface SpendingRule { id: number; merchant: string; category_name?: string; category_id?: number }
+export interface CategoryGroup { id: number; name: string }
+export interface CopyBudgetsResponse { copied: number; budgets?: { category_id: number; amount: number }[] }
+
 // A bill's month status. Mirrors the server's statusService.
 export type TrackerStatus =
   | 'paid' | 'autodraft' | 'upcoming' | 'due_soon' | 'late' | 'missed' | 'skipped';