feat: fn index extrae unit_tests automáticamente

El indexer lee test_file_path de funciones testeadas, parsea los test cases y los inserta en unit_tests. El output de fn index ahora muestra el conteo de unit_tests extraídos.

cmd/fn/main.go

@@ -123,7 +123,7 @@ func cmdIndex() {
 		}
 	}
 
-	fmt.Printf("Indexed %d functions, %d types, %d apps, %d analysis\n", result.Functions, result.Types, result.Apps, result.Analysis)
+	fmt.Printf("Indexed %d functions, %d types, %d apps, %d analysis, %d unit_tests\n", result.Functions, result.Types, result.Apps, result.Analysis, result.UnitTests)
 	for _, e := range result.ValidationErrors {
 		fmt.Fprintf(os.Stderr, "  INVALID: %s\n", e)
 	}

registry/indexer.go

@@ -14,6 +14,7 @@ type IndexResult struct {
 	Types            int
 	Apps             int
 	Analysis         int
+	UnitTests        int
 	ValidationErrors []string
 	Warnings         []string
 	Errors           []string
@@ -203,6 +204,39 @@ func Index(db *DB, root string) (*IndexResult, error) {
 		result.Analysis++
 	}
 
+	// Extract unit tests from test files of tested functions
+	if err := db.PurgeUnitTests(); err != nil {
+		result.Warnings = append(result.Warnings, fmt.Sprintf("purging unit_tests: %v", err))
+	}
+	for _, f := range functions {
+		if !f.Tested || f.TestFilePath == "" {
+			continue
+		}
+		absTestPath := filepath.Join(root, f.TestFilePath)
+		cases, err := parseTestFile(absTestPath, f.Lang)
+		if err != nil {
+			result.Warnings = append(result.Warnings, fmt.Sprintf("%s: parsing tests: %v", f.ID, err))
+			continue
+		}
+		for i, tc := range cases {
+			ut := &UnitTest{
+				ID:         fmt.Sprintf("%s_t%d", f.ID, i),
+				FunctionID: f.ID,
+				Name:       tc.Name,
+				Code:       tc.Code,
+				FilePath:   f.TestFilePath,
+				Lang:       f.Lang,
+				CreatedAt:  now,
+				UpdatedAt:  now,
+			}
+			if err := db.InsertUnitTest(ut); err != nil {
+				result.Warnings = append(result.Warnings, fmt.Sprintf("insert unit_test %s: %v", ut.ID, err))
+				continue
+			}
+			result.UnitTests++
+		}
+	}
+
 	// Post-insert: warn about file_path entries that don't exist on disk
 	for _, f := range functions {
 		if f.FilePath != "" {