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

drizzle/meta/_journal.json

@@ -16,5 +16,12 @@
       "tag": "0001_supreme_the_enforcers",
       "breakpoints": true
     }
+    ,{
+      "idx": 2,
+      "version": "7",
+      "when": 1775400000000,
+      "tag": "0002_tax_deductible",
+      "breakpoints": true
+    }
   ]
 }