0.8.3: custom tooltips, editor-hide, pack script, settings reshuffle

Tooltips
- New v-tooltip directive + TooltipHost floating panel replace the
  native title attribute across 95+ sites (topbar, timeline, sidebar,
  properties, stage overlays, fullscreen preview, export dialog,
  clipart drawer, modals). Styled dark card with a configurable
  label + optional help line for inline documentation; screen
  readers still get an aria-label when the panel is disabled.
- Settings → Interface toggle (`ruwio:tooltipsEnabled`) hides the
  visual panel for users who know the app. IconButton now routes
  its title prop through v-tooltip so every existing call site is
  tooltip-aware without churn.

Editor-hide + export filter
- New `Layer.editorHidden` flag, eye toggle per layer row, skipped
  by the Konva stage and the mask-preview canvas path but honoured
  by exports and fullscreen preview (runtime untouched).
- Export dialog gets a "Skip hidden tracks" switch that strips
  editor-hidden layers from every format (scene JS, runtime,
  example HTML, MP4, WebM) on opt-in. Disabled when the scene has
  no hidden layers.

Button editor
- `+` buttons appear on empty state slots in button-timeline rows
  and duplicate the nearest keyframe (prev by preference, next
  otherwise) onto that slot. New `duplicateKeyframeAt` store
  action carries props, easing, hold, and bezier handles across.

Stage / interaction
- Plain left-click on the empty content view pans the viewport,
  but only when the pointer isn't over a Konva shape — transformer
  handles, vertex dots, and selection boxes that extend past the
  canvas edge keep their drag.

Settings reshuffle
- Timeline tab merged into Document (Duration + FPS sit under a
  new "Timing" sub-heading). New Interface tab gathers three
  global prefs: Show tooltips, Show locked tracks, Asset
  thumbnails — driven by shared composables so the existing
  toolbar toggles stay in sync. Interface-tab CSS defensively
  resets the scoped label flex-column + uppercase rule that was
  making the toggle row look like an accident.

Project identity + UX polish
- Favicon wired up (moved to public/favicon.ico, linked from
  index.html); scripts/pack.sh packs the minimum Vue project
  (src, index.html, configs, public) into a tarball with the
  right version in the filename, and `npm run pack` drives it.
- About dialog now credits Torsten Hoeltge.

Test infra
- Progress bar turns red mid-run on the first failure: runAll
  gets an onResult callback that TestOverlay uses to push each
  result into the reactive array incrementally.
- mountComponent in the test harness registers v-tooltip on the
  isolated app instance so IconButton's aria-label contract
  actually fires under test.

Regression tests
- duplicateKeyframeAt: copy fidelity (props, easing, hold),
  collision refusal, unknown-id guards, separated-track targeting.
- Shared composables: useTooltipPref and useAssetThumbsPref both
  return the same ref across calls and persist to localStorage.
- Tooltip contract: IconButton ships `aria-label` (not title);
  live-DOM smoke tests match on aria-label selectors now.

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

src/stores/scene.ts

@@ -641,6 +641,37 @@ export const useSceneStore = defineStore('scene', {
       shift(layer.keyframes)
       shift(layer.positionKeyframes)
     },
+    /** Copy the referenced keyframe to a specific time. Carries easing,
+     *  hold, and control-point handles along; refuses if the target
+     *  time is already occupied in the same array. Used by the
+     *  button-editor's + buttons to fill empty state slots with the
+     *  previous (or next) keyframe's values. */
+    duplicateKeyframeAt(
+      layerId: string,
+      keyframeId: string,
+      targetTime: number,
+    ): string | null {
+      const layer = this.activeLayers.find((l) => l.id === layerId)
+      if (!layer) return null
+      const found = findKf(layer, keyframeId)
+      if (!found) return null
+      const { kf: source, arr } = found
+      if (arr.some((k) => Math.abs(k.time - targetTime) < KEYFRAME_EPSILON)) return null
+      const newKf: Keyframe = {
+        id: uid(),
+        time: targetTime,
+        props: { ...source.props },
+        easing: source.easing,
+      }
+      if (source.hold) newKf.hold = true
+      if (source.ctrlX !== undefined && source.ctrlY !== undefined) {
+        newKf.ctrlX = source.ctrlX
+        newKf.ctrlY = source.ctrlY
+      }
+      arr.push(newKf)
+      sortKfs(arr)
+      return newKf.id
+    },
     duplicateKeyframe(layerId: string, keyframeId: string): string | null {
       const layer = this.activeLayers.find((l) => l.id === layerId)
       if (!layer) return null
@@ -1225,6 +1256,12 @@ export const useSceneStore = defineStore('scene', {
         else delete group.locked
       }
     },
+    setLayerEditorHidden(layerId: string, hidden: boolean) {
+      const layer = this.activeLayers.find((l) => l.id === layerId)
+      if (!layer) return
+      if (hidden) layer.editorHidden = true
+      else delete layer.editorHidden
+    },
 
     // -------- Markers --------------------------------------------------