style(tsconvert): enforce two-space indentation for TypeScript interfaces

- Add two spaces before each field in generated interfaces
- Use newlines between fields and closing brace for proper formatting
- Update test to validate proper indentation
- Document test requirements in AGENTS.md

internal/functions/typescript_test.go

@@ -133,7 +133,7 @@ func TestResultStruct(t *testing.T) {
 	// Verify Declarations
 	defs := GetFunctionDeclarations()
 	assert.Contains(t, defs, "declare function result(input: string): TestResult;")
-	assert.Contains(t, defs, "interface TestResult {id: number; data: number[]}")
+	assert.Contains(t, defs, "interface TestResult {\n  id: number\n  data: number[]\n}")
 }
 
 type TestAsyncArgs struct {