feat(overlay): improve provisional text display and line splitting

README.md

@@ -64,7 +64,9 @@ Use `--output=both` to keep terminal output as well:
 ./scripts/distrobox/run.sh --mode=vad --output=both
 ```
 
-In VAD mode, a 500 ms pause finalizes the current caption and starts the next line. The overlay keeps up to six completed lines above the active provisional caption; each completed line remains visible for at least three seconds and gradually fades from white to a restrained gray as it ages. If a seventh line arrives sooner, the hard six-line cap removes the oldest. Text is left-aligned inside the centered, fixed-width dark bubble and wraps at its configured width instead of extending off-screen. Pointer input passes through the window by default. Empty completed captions hide the overlay.
+In VAD mode, a 500 ms pause finalizes the current speech segment. Captioneer splits that transcript again at sentence punctuation and at word-safe boundaries of at most 64 characters, so continuous speech does not become one enormous paragraph. The live provisional view keeps the latest three digestible chunks and grows vertically without ellipsizing them. Completed chunks remain visible for at least three seconds, receive extra time based on their word count, and gradually fade from white to a restrained gray as they age. When several chunks finalize together, their removal is staggered in reading order instead of deleting the whole block at once. Up to six completed chunks remain above the provisional text; if a seventh arrives, the oldest is removed. Blank recognition results never erase completed text before its reading lifetime expires.
+
+Text is left-aligned inside the centered, fixed-width dark bubble and wraps at its configured width instead of extending off-screen. Pointer input passes through the window by default.
 
 To build outside the helper script, install GTK4 and GTK4 Layer Shell development packages, then run: