fix: SQLite busy_timeout + stable concurrent tests

- Set PRAGMA busy_timeout=5000ms so concurrent reads wait instead of failing
- Fix flaky TestPhase6DualStream (was failing ~80% due to slow path goroutine lock)
- Tests now pass 5/5 consecutive runs

Author: Patel230

integration_test.go

@@ -631,18 +631,22 @@ func TestPhase6DualStream(t *testing.T) {
 	}
 
 	// Give slow path time to run and release DB lock
-	time.Sleep(200 * time.Millisecond)
-
-	// Verify temporal backbone edge exists
-	edges, _ := eng.Store().GetEdgesFrom(node.ID)
-	hasTemporalEdge := false
-	for _, e := range edges {
-		if e.ToID == node2.ID && e.Type == "learned_in" {
-			hasTemporalEdge = true
+	// Retry up to 500ms (slow path runs async)
+	var hasTemporalEdge bool
+	for i := 0; i < 10; i++ {
+		time.Sleep(50 * time.Millisecond)
+		edges, _ := eng.Store().GetEdgesFrom(node.ID)
+		for _, e := range edges {
+			if e.ToID == node2.ID && e.Type == "learned_in" {
+				hasTemporalEdge = true
+			}
+		}
+		if hasTemporalEdge {
+			break
 		}
 	}
 	if !hasTemporalEdge {
-		t.Error("dual stream: temporal backbone edge not created")
+		t.Error("dual stream: temporal backbone edge not created within 500ms")
 	}
 }
 

internal/storage/sqlite.go

@@ -61,6 +61,10 @@ func NewStore(dbPath string) (*Store, error) {
 	if err := db.Ping(); err != nil {
 		return nil, err
 	}
+	// Set busy timeout so concurrent reads wait instead of failing immediately
+	if _, err := db.Exec("PRAGMA busy_timeout = 5000"); err != nil {
+		return nil, err
+	}
 	s := &Store{db: db}
 	if err := s.createTables(); err != nil {
 		return nil, err