Fix all TypeScript errors: restore proper types and typed route casts

- Restore `as any` casts for Next.js typedRoutes on dynamic routes
- Use proper types for PDF templates, invoice/expense data, DB schema
- Fix PgColumn casts in sort helpers for expenses/invoices
- Add null guards for optional port/client in record-export
- Fix vitest config (remove invalid poolOptions)
- Lint: 0 errors, TypeScript: 0 errors

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

tests/unit/audit.test.ts

@@ -42,7 +42,7 @@ describe('diffFields', () => {
     const updated = { meta: { x: 1, y: 3 } };
     const result = diffFields(old, updated);
     expect(result).toHaveLength(1);
-    expect(result[0].field).toBe('meta');
+    expect(result[0]!.field).toBe('meta');
   });
 
   it('no diff when nested objects are deeply equal', () => {

tests/unit/entity-diff.test.ts

@@ -28,14 +28,14 @@ describe('diffEntity', () => {
   });
 
   it('detects null-to-value transition', () => {
-    const old = { note: null };
+    const old: Record<string, unknown> = { note: null };
     const result = diffEntity(old, { note: 'Hello' });
     expect(result.changed).toBe(true);
     expect(result.diff.note).toEqual({ old: null, new: 'Hello' });
   });
 
   it('detects value-to-null transition', () => {
-    const old = { note: 'Hello' };
+    const old: Record<string, unknown> = { note: 'Hello' };
     const result = diffEntity(old, { note: null });
     expect(result.changed).toBe(true);
     expect(result.diff.note).toEqual({ old: 'Hello', new: null });