fix: expand us-cpa extraction review and rendering

skills/us-cpa/tests/fixtures/documents/interest-1099.txt

@@ -0,0 +1,3 @@
+Form 1099-INT
+Recipient: Jane Doe
+Box 1 Interest Income 1750

skills/us-cpa/tests/fixtures/documents/simple-w2.txt

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+Form W-2 Wage and Tax Statement
+Employee: Jane Doe
+Box 1 Wages, tips, other compensation 50000
+Box 2 Federal income tax withheld 6000

skills/us-cpa/tests/fixtures/returns/simple-w2-interest-2025-normalized.json

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+{
+  "taxYear": 2025,
+  "filingStatus": "single",
+  "requiredForms": ["f1040", "f1040sb"],
+  "income": {
+    "wages": 50000.0,
+    "taxableInterest": 1750.0,
+    "businessIncome": 0.0,
+    "capitalGainLoss": 0.0,
+    "rentalIncome": 0.0
+  },
+  "totals": {
+    "adjustedGrossIncome": 51750.0,
+    "taxableIncome": 36000.0
+  }
+}