Add Fetch Request pipeline UI with real-time SSEs (#8)

## Summary

Add Fetch Request pipeline UI with real-time SSE progress tracking, ambiguity resolution, list page with filtering/retry, and detail page with stepper/event feed.

## Changes

### New files

- **`src/FetchRequestDetail.tsx`** (+675 lines) — Full detail page for a single fetch request with:
  - SSE connection for real-time pipeline progress (`/fetch-requests/:id/events`)
  - 4-step stepper (Extract → Raw Expense → Enrich → Save) with active/completed/failed/paused states
  - Granular progress bar (10% Extract, 20% Raw Expense, 50% Enrich, 20% Save)
  - Progress event feed with auto-scroll and deduplication (only latest `progress` per step, hides `started` when terminal event follows)
  - Ambiguity resolution cards with candidate selection buttons
  - Retry support with retry-count progress bar
  - Failure/success snackbar notifications
  - Error display for failed fetch requests

### Modified files

- **`react-openapi/api/client.ts`** — added `api.patch()` method for PATCH requests
- **`react-openapi/hooks/useResource.ts`** — added `usePatch()` mutation hook for partial updates with cache invalidation
- **`src/FetchRequests.tsx`** (+347/−73 lines) — Major list page rewrite:
  - Row-level actions: retry (failed <3 retries), navigate to detail (paused), delete with confirmation dialog
  - Filter bar: status multi-select, account text filter, file/email source toggle
  - Account name autocomplete from API
  - Format dropdown driven by `resourceOverrides` config
  - Date pickers (changed from `datetime-local` to `date`)
  - Copy fingerprint button, retry count display, date range column
  - Row click navigates to detail, sorted by `created_at` desc
  - `pause` status support in `statusColors`
  - 409 conflict handling on duplicate fingerprint
  - `formatApiError()` for 422 validation error display
- **`src/features/fetch-requests/fetch-requests.models.ts`** — Added types:
  - `paused` to `FetchRequestStatus`
  - `FetchRequestUpdate` interface
  - `retry_count` to `FetchRequest` interface
  - `raw_lines`, `txn_blocks`, `txn_dicts`, `txn_dict_count`/`txn_dicts_count` to source types
  - `PendingAmbiguity`, `AmbiguityCandidate`, `ResolveAmbiguityPayload`
  - `SSEEvent`, `SSEEventStep`, `SSEEventStatus`, `ProgressMessage`
  - `FetchRequestFilters`
  - `formatApiError()` helper for FastAPI 422 error parsing
  - `RETRY_MAX = 3` constant
- **`src/features/fetch-requests/index.ts`** — Barrel exports for all new types, hooks, and helpers
- **`src/features/fetch-requests/useFetchRequests.ts`** — Added hooks:
  - `useUpdateFetchRequest()` — PATCH via `usePatch`
  - `useFetchRequestAmbiguities(id)` — queries `/fetch-requests/:id/ambiguities`
  - `useResolveAmbiguity()` — posts to `/ambiguities/:id/resolve` with cache invalidation
- **`src/main.jsx`** — Added route `/fetch-requests/:id` → `FetchRequestDetail`

## Key decisions

- SSE event stream is the single source of truth for progress; REST is only fallback for page load
- Stepper shows granular ratio-based progress counts (e.g. `150/246` for enrich)
- `pipeline/failed` SSE event triggers refetch + error snackbar
- `load_content` events excluded from event feed entirely
- Enrich/Save progress counts come only from SSE (no REST fallback since those phases don't pause)

Reviewed-on: #8
Co-authored-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>
Co-committed-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>

react-openapi/api/client.ts

@@ -46,6 +46,10 @@ export const api = {
     if (!_api) throw new Error("API client not initialized");
     return _api.delete(...args);
   },
+  patch: (...args: Parameters<AxiosInstance["patch"]>) => {
+    if (!_api) throw new Error("API client not initialized");
+    return _api.patch(...args);
+  },
 };
 
 export const auth = {

react-openapi/hooks/useResource.ts

@@ -73,6 +73,23 @@ export function useResource<T = any>(config: ResourceConfig | undefined) {
       },
     });
 
+  // --- PATCH ---
+  const usePatch = () =>
+    useMutation({
+      mutationFn: async ({ id, data }: { id: string; data: Partial<T> }) => {
+        if (!endpoint) throw new Error("Endpoint not defined");
+        // @ts-ignore
+        const res = await api.patch<T>(`${endpoint}/${id}`, data);
+        return res.data;
+      },
+      onSuccess: (updatedItem) => {
+        // @ts-ignore
+        const id = updatedItem[primaryKey];
+        queryClient.invalidateQueries({ queryKey: [name, "list"] });
+        queryClient.invalidateQueries({ queryKey: [name, "detail", id] });
+      },
+    });
+
   // --- DELETE ---
   const useDelete = () =>
     useMutation({
@@ -136,6 +153,7 @@ export function useResource<T = any>(config: ResourceConfig | undefined) {
     useMe,
     useCreate,
     useUpdate,
+    usePatch,
     useUpdateMe,
     useDelete,
     getListQueryOptions,