fix: resolve 5 invoice/payment issues from user feedback

- Replace misleading 'sent' status with 'pending' (no email capability)
- Show assessment group name instead of raw 'regular_assessment' type
- Add owner last name to invoice table
- Fix payment creation Internal Server Error (PostgreSQL $2 type cast)
- Add edit/delete capability for payment records with invoice recalc

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

db/migrations/012-invoice-status-pending.sql

@@ -0,0 +1,33 @@
+-- Migration 012: Replace 'sent' status with 'pending' for invoices
+-- 'sent' implied email delivery which doesn't exist; 'pending' is more accurate
+
+DO $$
+DECLARE
+  v_schema TEXT;
+  v_constraint TEXT;
+BEGIN
+  FOR v_schema IN
+    SELECT schema_name FROM information_schema.schemata
+    WHERE schema_name LIKE 'tenant_%'
+  LOOP
+    -- Find and drop the existing status check constraint
+    SELECT constraint_name INTO v_constraint
+    FROM information_schema.table_constraints
+    WHERE table_schema = v_schema
+      AND table_name = 'invoices'
+      AND constraint_type = 'CHECK'
+      AND constraint_name LIKE '%status%';
+
+    IF v_constraint IS NOT NULL THEN
+      EXECUTE format('ALTER TABLE %I.invoices DROP CONSTRAINT %I', v_schema, v_constraint);
+    END IF;
+
+    -- Add new constraint that includes 'pending'
+    EXECUTE format('ALTER TABLE %I.invoices ADD CONSTRAINT invoices_status_check CHECK (status IN (
+      ''draft'', ''pending'', ''sent'', ''paid'', ''partial'', ''overdue'', ''void'', ''written_off''
+    ))', v_schema);
+
+    -- Convert existing 'sent' invoices to 'pending'
+    EXECUTE format('UPDATE %I.invoices SET status = ''pending'' WHERE status = ''sent''', v_schema);
+  END LOOP;
+END $$;