fix(enable-banking): reliable initial backfill, no more silent ~30-day windows (#443) (#486)

* fix(enable-banking): reliable initial backfill, no more silent ~30-day windows (#443)

PSD2 first-sync was a compound bug: the cron runs once daily so users got no
data for up to 24h after activation; the "Sync now" button defaulted to 30
days and set last_synced_at, permanently locking the cron into 7-day
incremental mode and discarding the 90-day backfill window. ASPSPs also
truncate history below requested ranges, but the discrepancy was only logged.

This change:

- Runs the initial backfill inline when the user finishes account selection
  (PATCH /accounts), so data is available the moment they finish onboarding.
- Tracks initial_sync_completed_at separately from last_synced_at; the cron
  now gates first-sync 90-day window on that, so manual syncs no longer
  clobber the backfill path.
- Surfaces the actual returned date range to the UI ("Initial historik: X → Y
  (begärde Z)") with a warning when the bank truncated history.
- Defaults manual /sync to 90 days (was 30) — matches user intent.
- AccountPickerDialog uses SpeedLedger's SIE-anchor pattern when an SIE
  import covers prior periods (auto-defaults lookback to "day after last SIE
  entry"), with Bokio-style PSD2 disclosure on the standard path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(enable-banking): address review feedback on PR #486

Two fixes from review:

1. Memoise the browser Supabase client in AccountPickerDialog. createClient()
   in the component body returned a new reference every render, and `supabase`
   was in the SIE-fetch effect's dep array — every checkbox tick or parent
   re-render re-fired the SIE-imports query.

2. Drop `accounts_data` from the second supabase update inside the activation
   backfill. The first update already wrote it; including it here races with
   any concurrent writer (e.g. cron firing in the sub-60s window) and would
   silently overwrite. Only initial_sync_* metadata + last_synced_at need to
   be persisted in the second update.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(enable-banking): check metadata-update error after inline backfill

The second supabase.update() inside the activation backfill block didn't
check its error return. Supabase client methods don't throw on DB errors;
they return { data, error }. If the metadata write failed (network blip,
RLS quirk, etc.), the handler still populated initialSyncSummary and
returned success — UI saw "imported N transactions" while the DB had
initial_sync_completed_at = NULL, causing the cron to schedule another
full 90-day backfill the next morning.

Capture { error } from the metadata update. On failure, surface as
initial_sync_error with a metadata_update_failed: prefix and skip the
initialSyncSummary population. The cron's gate (initial_sync_completed_at
IS NULL) still self-heals on the next run; this just keeps the UI honest
about which path got us there.

New test stub: SupabaseStub.updateErrorByCall lets a test succeed the
first update and fail the second.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/api/extensions/enable-banking/sync/cron/route.ts

@@ -131,7 +131,10 @@ export const GET = withCronContext('cron.bank_sync', async (_request, ctx) => {
 
       const toDate = new Date().toISOString().split('T')[0]
       // First sync: 90-day lookback (PSD2 max). Subsequent: 7-day window.
-      const isFirstSync = !connection.last_synced_at
+      // Gate on initial_sync_completed_at, not last_synced_at — manual "Sync now"
+      // sets last_synced_at without doing the deep backfill, and we want the cron
+      // to still fall back to 90 days if the inline activation backfill failed.
+      const isFirstSync = !connection.initial_sync_completed_at
       const lookbackDays = isFirstSync ? 90 : 7
       if (isFirstSync) {
         ctx.log.info('first sync for connection — using 90-day lookback', {
@@ -218,11 +221,27 @@ export const GET = withCronContext('cron.bank_sync', async (_request, ctx) => {
 
       // Successful sync: update connection and clear any previous error state.
       // Write allAccounts (not accounts) so disabled accounts stay in the row.
+      const completedAt = new Date().toISOString()
+      let initialSyncFields: Record<string, unknown> = {}
+      if (isFirstSync) {
+        // Aggregate returned booking dates across enabled accounts so the UI
+        // can show "we requested X but the bank returned Y to Z".
+        const minDates = syncResults.map(r => r.returnedMinBookingDate).filter((d): d is string => !!d)
+        const maxDates = syncResults.map(r => r.returnedMaxBookingDate).filter((d): d is string => !!d)
+        initialSyncFields = {
+          initial_sync_completed_at: completedAt,
+          initial_sync_requested_from: fromDate,
+          initial_sync_returned_min_date: minDates.length > 0 ? minDates.reduce((a, b) => (a < b ? a : b)) : null,
+          initial_sync_returned_max_date: maxDates.length > 0 ? maxDates.reduce((a, b) => (a > b ? a : b)) : null,
+          initial_sync_lookback_days: lookbackDays,
+        }
+      }
       await supabase
         .from('bank_connections')
         .update({
           accounts_data: allAccounts,
-          last_synced_at: new Date().toISOString(),
+          last_synced_at: completedAt,
+          ...initialSyncFields,
           ...(connection.error_message ? { error_message: null } : {}),
         })
         .eq('id', connection.id)