Fix/balance inconsitency (#306)

* feat: implement fiscal period date fields component and validation logic

* feat: update fiscal period validation and naming logic

* feat: implement RPC for computing prior opening balances

- Added `compute_prior_opening_balances` RPC to aggregate opening balances for balance-sheet accounts when no opening balance entry is set.
- Updated tests across various reports to utilize the new RPC for fetching prior balances.
- Refactored `getOpeningBalances` to call the RPC when necessary, improving performance and reliability.
- Introduced a script to repair fiscal period chains for companies with broken periods, ensuring proper linking and continuity.
- Enhanced error handling and validation in the repair script to ensure data integrity during the process.

* feat: implement duplicate opening-balance repair for multi-year SIE imports

* feat: enhance SIE entry listing and deduplication logic for opening balances

* fix: refine companyHasPriorActivity logic to exclude storno entries and improve balance counting

components/import/ImportReviewStep.tsx

@@ -82,7 +82,7 @@ export default function ImportReviewStep({
           .from('company_settings')
           .select('default_voucher_series')
           .eq('company_id', company.id)
-          .single(),
+          .maybeSingle(),
         supabase
           .from('voucher_sequences')
           .select('voucher_series')
@@ -91,8 +91,7 @@ export default function ImportReviewStep({
 
       if (cancelled) return
 
-      // PGRST116 = no rows returned from .single(); expected when settings not yet created.
-      if (settingsError && settingsError.code !== 'PGRST116') {
+      if (settingsError) {
         console.error('Failed to load company settings for voucher series', settingsError)
       }
       if (sequencesError) {