Move StartTime initialization to application startup hook

- Remove StartTime initialization from globals.New()
- Add setupGlobals function in app.go to set StartTime during fx OnStart
- Simplify globals package to be just a key/value store
- Remove fx dependencies from globals test

internal/database/database.go

@@ -141,3 +141,8 @@ func (db *DB) createSchema(ctx context.Context) error {
 	_, err := db.conn.ExecContext(ctx, schema)
 	return err
 }
+
+// NewTestDB creates an in-memory SQLite database for testing
+func NewTestDB() (*DB, error) {
+	return New(context.Background(), ":memory:")
+}