feat: complete sentences mode with Star Wars effect and line transitions

- Implement two-line layout with Star Wars perspective (top line 80% size)
- Add smooth line transition animation when first line completes
- First line explodes independently, second line grows and moves down
- Fix space handling at line breaks (space included in first line)
- Ship stays centered for sentences mode
- Support punctuation input (commas, periods, exclamation, question marks)
- Reduce font size to 20px for better readability
- Set falling speed to 25 pixels/second for sentences

src/types.ts

@@ -34,6 +34,9 @@ export type FallingLetter = {
   // For word/sentence/paragraph modes
   fullText?: string; // The complete word/sentence/paragraph
   charIndex?: number; // Current character index being typed (0-based)
+  // For line transitions in sentences/paragraphs
+  lineTransition?: boolean;
+  lineTransitionTime?: number;
 };
 
 // ============================================================================