0.8.1: dirty-state + Cmd/Ctrl+S, fullscreen plays to OUT, UX fixes

- Unsaved-changes indicator: a small accent dot appears on the save
  button whenever the scene has changed since the last save/load.
  Save/load/new all mark the project clean on next tick.
- Cmd/Ctrl+S saves the project (reuses the same flow as the button;
  prompts for a name on first save). Tooltip now mentions the
  shortcut.
- Fullscreen preview plays to the OUT marker (or scene.duration when
  no OUT is set) instead of looping at the last keyframe. Dropped
  the runtime's effectiveEnd helper; RUNTIME_VERSION 13 → 14.
- "Still frame" keyframes no longer disable easing. A held kf's
  easing still drives the segment INTO it from the previous kf, so
  you can ease into a pause. Only the first kf disables easing
  (nothing precedes it). Dropped `timeline.holdDisabledHint`.
- Settings dialog: hint text 11px → 13px (and dropped italic) so
  the inline help is readable; section headings 10px → 13px.
- Canvas stage shadow: `shadowCfg` always emits explicit values plus
  a `shadowEnabled` flag instead of returning `{}`. Konva's default
  shadowOpacity is 1, so bailing with `{}` could leave stale shadow
  attrs on the shape. Preview and editor now gate on the same
  condition deterministically.
- Sidebar empty-state copy: "No clips" → "No clips yet" to match
  "No buttons yet".

Regression tests: runtime rangeOut fallback is scene.duration (not
last kf); sidebar empty-states both contain "yet"; the
holdDisabledHint key is gone; saveProject tooltips mention the
shortcut.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

todo

@@ -132,8 +132,9 @@ der clip-art drawer muss bevor er reingeschoben wird schon so tun als hätte er
 
 
 
+die inline hilfe texte in den settings sind zu klein. das kann man nicht lesen
 
-
+warum ist eigentlich still frame easing disabled? man muss doch zu einem still-frame hin easen können. verstehe den grund nicht
 
 
 
@@ -142,3 +143,5 @@ der clip-art drawer muss bevor er reingeschoben wird schon so tun als hätte er
 
 
  ich würde an dieser stelle mal ein paar regression-tests hinzufügen und dann committen
+
+wenn man den leeren teil des content-views zieht (außerhalb der canvas constraints) muss canvas move auch ohne control key gehen