feat: delete last voucher, notes field, schema cache fix (#230)

* feat: delete last voucher, notes field, schema cache fix

Address three customer feedback items from William (wigu.se):

1. Delete last voucher per series (Fortnox model):
   - New `delete_last_voucher` RPC with full safety checks (last-in-series,
     open period, no references, owner/admin only)
   - Session variable bypass for immutability/retention/line triggers
   - Full JSONB audit trail (BFNAR 2013:2 behandlingshistorik)
   - DELETE endpoint + UI with confirmation dialogs
   - Storno restoration when deleting a reversal entry

2. Notes/comment field on vouchers:
   - `notes` column on journal_entries (always-editable internal metadata)
   - Immutability trigger updated to allow notes-only updates on posted entries
   - PATCH endpoint, inline-edit UI on detail page, form textarea

3. Schema cache fix:
   - NOTIFY pgrst applied to production (immediate fix)
   - Retroactive migration + CLAUDE.md migration rule added

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: address Greptile review — tighten trigger, lock voucher sequence

P1: The notes-only exception in enforce_journal_entry_immutability was
too broad — it only checked 7 verifikation fields, allowing silent
mutation of correction_of_id, reverses_id, reversed_by_id, committed_at,
and user_id on posted entries. Now guards all metadata fields; only
notes and updated_at may differ.

P2: Lock voucher_sequences row FOR UPDATE before the MAX(voucher_number)
check in delete_last_voucher to serialise against concurrent
commit_journal_entry calls, preventing voucher number gaps.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

components/import/BankFileConfirmStep.tsx

@@ -128,7 +128,7 @@ export default function BankFileConfirmStep({
 
             <div className="p-4 bg-muted/50 rounded-lg">
               <div className="flex items-center gap-2 text-muted-foreground mb-1">
-                <span className="text-xs">Utgifter</span>
+                <span className="text-xs">Leverantörsfakturor</span>
               </div>
               <p className="text-xl font-display font-medium tabular-nums">
                 {formatCurrency(stats.total_expenses)}

components/import/BankFilePreviewStep.tsx

@@ -85,7 +85,7 @@ export default function BankFilePreviewStep({
           <CardContent className="pt-6">
             <div className="flex items-center gap-2 text-muted-foreground mb-1">
               <TrendingDown className="h-4 w-4" />
-              <span className="text-sm">Utgifter</span>
+              <span className="text-sm">Leverantörsfakturor</span>
             </div>
             <p className="text-lg font-display font-medium tabular-nums">
               {formatCurrency(stats.total_expenses)}