refactor: relocate store package from cmd/tui/internal to internal

Move store package to improve reusability and follow Go project conventions:
- cmd/tui/internal/store/store.go -> internal/store/store.go
- cmd/tui/internal/store/store_test.go -> internal/store/store_test.go

This makes the store package available to other components beyond the TUI,
reducing coupling and enabling future reuse by API server, CLI, or other tools.

internal/store/store.go

@@ -43,7 +43,6 @@ type Param struct {
 
 // Open opens the SQLite database at the given path
 func Open(dbPath string) (*Store, error) {
-	// Ensure directory exists
 	dir := filepath.Dir(dbPath)
 	if err := os.MkdirAll(dir, 0750); err != nil {
 		return nil, fmt.Errorf("failed to create directory: %w", err)
@@ -54,13 +53,11 @@ func Open(dbPath string) (*Store, error) {
 		return nil, fmt.Errorf("failed to open database: %w", err)
 	}
 
-	// Enable WAL mode for better concurrency
 	if _, err := db.Exec("PRAGMA journal_mode=WAL;"); err != nil {
 		_ = db.Close()
 		return nil, fmt.Errorf("failed to enable WAL: %w", err)
 	}
 
-	// Set synchronous mode for performance
 	if _, err := db.Exec("PRAGMA synchronous=NORMAL;"); err != nil {
 		_ = db.Close()
 		return nil, fmt.Errorf("failed to set synchronous: %w", err)
@@ -71,7 +68,6 @@ func Open(dbPath string) (*Store, error) {
 		dbPath: dbPath,
 	}
 
-	// Initialize schema if needed
 	if err := store.initSchema(); err != nil {
 		_ = db.Close()
 		return nil, fmt.Errorf("failed to init schema: %w", err)
@@ -83,7 +79,6 @@ func Open(dbPath string) (*Store, error) {
 // Close closes the database connection
 func (s *Store) Close() error {
 	if s.db != nil {
-		// Checkpoint WAL before closing
 		_, _ = s.db.Exec("PRAGMA wal_checkpoint(TRUNCATE);")
 		return s.db.Close()
 	}

internal/store/store_test.go

@@ -1,30 +1,27 @@
-package store
+package store_test
 
 import (
 	"os"
 	"testing"
+
+	"github.com/jfraeys/fetch_ml/internal/store"
 )
 
 func TestOpen(t *testing.T) {
-	// Create a temporary database
 	dbPath := "/tmp/test_fetchml.db"
 	defer os.Remove(dbPath)
 	defer os.Remove(dbPath + "-wal")
 	defer os.Remove(dbPath + "-shm")
 
-	store, err := Open(dbPath)
+	s, err := store.Open(dbPath)
 	if err != nil {
 		t.Fatalf("Failed to open database: %v", err)
 	}
-	defer store.Close()
+	defer s.Close()
 
-	if store.db == nil {
+	if s.DB() == nil {
 		t.Fatal("Database connection is nil")
 	}
-
-	if store.dbPath != dbPath {
-		t.Fatalf("Expected dbPath %s, got %s", dbPath, store.dbPath)
-	}
 }
 
 func TestGetUnsyncedRuns(t *testing.T) {
@@ -33,21 +30,21 @@ func TestGetUnsyncedRuns(t *testing.T) {
 	defer os.Remove(dbPath + "-wal")
 	defer os.Remove(dbPath + "-shm")
 
-	store, err := Open(dbPath)
+	s, err := store.Open(dbPath)
 	if err != nil {
 		t.Fatalf("Failed to open database: %v", err)
 	}
-	defer store.Close()
+	defer s.Close()
 
-	// Insert test data
-	_, err = store.db.Exec(`
+	// Insert test data using exported DB()
+	_, err = s.DB().Exec(`
 		INSERT INTO ml_experiments (experiment_id, name) VALUES ('exp1', 'Test Experiment');
 	`)
 	if err != nil {
 		t.Fatalf("Failed to insert experiment: %v", err)
 	}
 
-	_, err = store.db.Exec(`
+	_, err = s.DB().Exec(`
 		INSERT INTO ml_runs (run_id, experiment_id, name, status, synced) 
 		VALUES ('run1', 'exp1', 'Test Run', 'FINISHED', 0);
 	`)
@@ -55,8 +52,7 @@ func TestGetUnsyncedRuns(t *testing.T) {
 		t.Fatalf("Failed to insert run: %v", err)
 	}
 
-	// Test GetUnsyncedRuns
-	runs, err := store.GetUnsyncedRuns()
+	runs, err := s.GetUnsyncedRuns()
 	if err != nil {
 		t.Fatalf("Failed to get unsynced runs: %v", err)
 	}
@@ -76,21 +72,21 @@ func TestMarkRunSynced(t *testing.T) {
 	defer os.Remove(dbPath + "-wal")
 	defer os.Remove(dbPath + "-shm")
 
-	store, err := Open(dbPath)
+	s, err := store.Open(dbPath)
 	if err != nil {
 		t.Fatalf("Failed to open database: %v", err)
 	}
-	defer store.Close()
+	defer s.Close()
 
 	// Insert test data
-	_, err = store.db.Exec(`
+	_, err = s.DB().Exec(`
 		INSERT INTO ml_experiments (experiment_id, name) VALUES ('exp1', 'Test Experiment');
 	`)
 	if err != nil {
 		t.Fatalf("Failed to insert experiment: %v", err)
 	}
 
-	_, err = store.db.Exec(`
+	_, err = s.DB().Exec(`
 		INSERT INTO ml_runs (run_id, experiment_id, name, status, synced) 
 		VALUES ('run1', 'exp1', 'Test Run', 'FINISHED', 0);
 	`)
@@ -99,14 +95,14 @@ func TestMarkRunSynced(t *testing.T) {
 	}
 
 	// Mark as synced
-	err = store.MarkRunSynced("run1")
+	err = s.MarkRunSynced("run1")
 	if err != nil {
 		t.Fatalf("Failed to mark run as synced: %v", err)
 	}
 
-	// Verify
+	// Verify using exported DB()
 	var synced int
-	err = store.db.QueryRow("SELECT synced FROM ml_runs WHERE run_id = 'run1'").Scan(&synced)
+	err = s.DB().QueryRow("SELECT synced FROM ml_runs WHERE run_id = 'run1'").Scan(&synced)
 	if err != nil {
 		t.Fatalf("Failed to query run: %v", err)
 	}