[raiseCatError]

Stacked on #531 (c3620236).

Bug (reproduced in Kitty 0.49.2): any key press, scroll, resize or handover turned the native welcome image into character art for the rest of the session, even with Logo animation Off. cancelMotion() set still, released every upload, and frame() painted with cellsOnly = this.still. Introduced in 8d625b28 (#521 stack); dev is not affected.

Fix (src/welcome/startup.ts):

• Stopping playback still stops the timer at once and deletes uploaded playback frames (generated logo frames or GIF/APNG frames).
• A still already on screen (Off, a finished Once, a still-image effect) is kept: no delete and re-send, no flicker.
• The live paint never forces character art; the archived card (snapshot.still) stays portable character art as before.
• dispose() releases everything explicitly.

Tests

• New: tests/welcomeLogoAnimation.test.ts: "a key press keeps the native still…". It fails on c3620236 and passes with the fix.
• Updated expectations in tests/welcomePlayback.test.ts: after input, frames and timers are freed and playback can't restart, and the repaint shows one native still upload. Scrolling repaints immediately.
• Focused: welcomeLogoAnimation, welcomePlayback, welcomeRuntime, welcome, welcomeEditor, uiConsistency: 56/56. tsc --noEmit is clean. The full suite is left to CI.

Physical QA (disposable Kitty 0.49.2, private HOME and Kitty config, Auto graphics, this build):

• Off: native image after a key and after Backspace (6 placeholder rows each).
• Assemble interrupted by a key: the native still appears at once and stays.
• Before the fix, the same steps produced character art.
• Ghostty was not physically tested for this change.