Add tax features: summary report, deductible expenses, invoice tax fix, CSV export

- Add taxDeductible boolean to expenses schema + migration 0002
- Update expenses router, form, and list to support tax-deductible flag
- Fix invoice-view tax calculation (was hardcoded $0.00; now uses taxRate)
- New Tax Summary tab in Reports: year selector, income/deductions breakdown,
  SE tax + federal income estimates, quarterly bar chart
- CSV export for accountant with income + expense rows and tax summary

https://claude.ai/code/session_012sqEgNQpx676isepeoX4Mi

src/server/db/migrate.ts

@@ -160,6 +160,16 @@ async function isMigrationApplied(client: Pool, tag: string): Promise<boolean> {
     `);
     return parseInt(rows[0]?.count ?? "0") > 0;
   }
+  if (tag === "0002_tax_deductible") {
+    // 0002 adds taxDeductible to beenvoice_expense
+    const { rows } = await client.query<{ count: string }>(`
+      SELECT COUNT(*)::text AS count FROM information_schema.columns
+      WHERE table_schema = 'public'
+        AND table_name = 'beenvoice_expense'
+        AND column_name = 'taxDeductible'
+    `);
+    return parseInt(rows[0]?.count ?? "0") > 0;
+  }
   // Unknown migration — assume not applied so it runs
   return false;
 }