Add Re-sync button for SimpleFIN connections

Resets LastSyncAt on all linked accounts so the next sync
re-fetches the full 90-day transaction window. Duplicate
detection prevents re-importing existing transactions.

- POST /api/bank-sync/connections/{id}/reset-sync endpoint
- Re-sync button shown only on SimpleFIN connection cards

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/services/bankSync.ts

@@ -46,6 +46,9 @@ export const bankSyncApi = {
   updateLinkedAccount: (linkedAccountId: string, data: { accountId: string | null; isEnabled: boolean }) =>
     api.put<LinkedAccountInfo>(`/bank-sync/linked-accounts/${linkedAccountId}`, data),
 
+  resetSync: (connectionId: string) =>
+    api.post(`/bank-sync/connections/${connectionId}/reset-sync`),
+
   syncNow: (connectionId: string) =>
     api.post(`/bank-sync/connections/${connectionId}/sync-now`),
 

frontend/src/views/settings/SettingsView.vue

@@ -184,6 +184,16 @@
               >
                 Sync Now
               </v-btn>
+              <v-btn
+                v-if="conn.provider === 'SimpleFIN'"
+                variant="tonal"
+                color="secondary"
+                prepend-icon="mdi-refresh"
+                :loading="resyncingConnections[conn.id]"
+                @click="resyncFromScratch(conn)"
+              >
+                Re-sync
+              </v-btn>
               <v-btn
                 variant="tonal"
                 :color="conn.isActive ? 'warning' : 'success'"
@@ -530,6 +540,7 @@ const connections = ref<SyncConnection[]>([])
 const accounts = ref<Account[]>([])
 const syncIntervals = reactive<Record<string, number>>({})
 const syncingConnections = reactive<Record<string, boolean>>({})
+const resyncingConnections = reactive<Record<string, boolean>>({})
 
 // Plaid credentials
 const plaidCredentials = ref<PlaidCredentials>({ isConfigured: false, environment: 'sandbox' })
@@ -814,6 +825,20 @@ async function syncNow(conn: SyncConnection) {
   }
 }
 
+async function resyncFromScratch(conn: SyncConnection) {
+  resyncingConnections[conn.id] = true
+  try {
+    await bankSyncApi.resetSync(conn.id)
+    await bankSyncApi.syncNow(conn.id)
+    syncingConnections[conn.id] = true
+  } catch (err: any) {
+    errorMessage.value = err.response?.data?.error || 'Re-sync failed'
+    showError.value = true
+  } finally {
+    resyncingConnections[conn.id] = false
+  }
+}
+
 // Handle sync results via SignalR notification
 const { notifications } = useNotifications()
 watch(notifications, (notifs) => {

src/Purrse.Api/Controllers/BankSyncController.cs

@@ -74,6 +74,13 @@ public class BankSyncController : ControllerBase
     public async Task<ActionResult<LinkedAccountResponse>> UpdateLinkedAccount(Guid id, UpdateLinkedAccountRequest request)
         => Ok(await _bankSyncService.UpdateLinkedAccountAsync(UserId, id, request));
 
+    [HttpPost("connections/{id}/reset-sync")]
+    public async Task<IActionResult> ResetSync(Guid id)
+    {
+        await _bankSyncService.ResetSyncDatesAsync(UserId, id);
+        return NoContent();
+    }
+
     [HttpPost("connections/{id}/sync-now")]
     public IActionResult SyncNow(Guid id)
     {

src/Purrse.Api/Services/BankSyncService.cs

@@ -311,6 +311,23 @@ public class BankSyncService : IBankSyncService
 
     // --- Sync ---
 
+    public async Task ResetSyncDatesAsync(Guid userId, Guid connectionId)
+    {
+        var connection = await _db.SyncConnections
+            .Include(c => c.LinkedAccounts)
+            .FirstOrDefaultAsync(c => c.Id == connectionId && c.UserId == userId)
+            ?? throw new KeyNotFoundException("Connection not found");
+
+        foreach (var la in connection.LinkedAccounts)
+        {
+            la.LastSyncAt = null;
+        }
+
+        connection.LastSyncAt = null;
+        connection.UpdatedAt = DateTime.UtcNow;
+        await _db.SaveChangesAsync();
+    }
+
     public async Task<SyncResultResponse> SyncNowAsync(Guid userId, Guid connectionId)
     {
         var connection = await _db.SyncConnections

src/Purrse.Core/Interfaces/Services/IBankSyncService.cs

@@ -28,6 +28,7 @@ public interface IBankSyncService
 
     // Sync
     Task<SyncResultResponse> SyncNowAsync(Guid userId, Guid connectionId);
+    Task ResetSyncDatesAsync(Guid userId, Guid connectionId);
     Task<SyncResultResponse> SyncAllAsync(Guid userId);
 
     // Logs