added driverjs onboarding

src/components/WelcomeModal.tsx

@@ -0,0 +1,30 @@
+interface WelcomeModalProps {
+  onStart: () => void
+  onSkip: () => void
+}
+
+export default function WelcomeModal({ onStart, onSkip }: WelcomeModalProps) {
+  return (
+    <div className="welcome-modal-overlay" onClick={onSkip}>
+      <div className="welcome-modal" onClick={(e) => e.stopPropagation()}>
+        <div className="welcome-modal-icon">
+          <svg width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round">
+            <path d="M12 21.35l-1.45-1.32C5.4 15.36 2 12.28 2 8.5 2 5.42 4.42 3 7.5 3c1.74 0 3.41.81 4.5 2.09C13.09 3.81 14.76 3 16.5 3 19.58 3 22 5.42 22 8.5c0 3.78-3.4 6.86-8.55 11.54L12 21.35z" />
+          </svg>
+        </div>
+        <h2 className="welcome-modal-title">Welcome to Grateful Journal</h2>
+        <p className="welcome-modal-text">
+          A private, peaceful space to capture what you're grateful for — every day.
+          Your entries are end-to-end encrypted, so only you can read them.
+          No feeds, no noise — just you and your thoughts.
+        </p>
+        <button className="welcome-modal-btn" onClick={onStart}>
+          Start Your Journey
+        </button>
+        <button className="welcome-modal-skip" onClick={onSkip}>
+          Skip tour
+        </button>
+      </div>
+    </div>
+  )
+}