0.18.2: centre crosshair + locked-track selection + eye-on-lock

- Optional centre crosshair: dashed horizontal + vertical lines
  through the effective canvas centre, togglable from the HUD next
  to the crop / mask-preview / stage-preview buttons. Scales with
  zoom and stays visible inside clip-edit.
- Locked clip tracks now behave as if they weren't on the stage —
  the ci-group is listening:false + draggable:false, so selection,
  drag, and transform all pass through. deselectIfLocked also
  clears a clip-instance selection that just got locked out
  (directly or via a parent group).
- Eye toggle stays clickable on locked layer / clip-track rows —
  previous pointer-events:none rule only whitelisted the lock
  button. Hide-in-editor is orthogonal to lock.

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

src/components/CanvasStage.vue

@@ -5,6 +5,7 @@ import {
   PhCircle,
   PhCornersIn,
   PhCrop,
+  PhCrosshair,
   PhCursorClick,
   PhFrameCorners,
   PhMaskHappy,
@@ -56,6 +57,10 @@ const viewX = ref(0)
 const viewY = ref(0)
 const cropObjects = ref(false)
 const maskPreview = ref(false)
+// Dashed horizontal + vertical lines through the center of the
+// effective canvas — a composition guide the user can toggle on/off
+// from the HUD. Not persisted; local to this editor session.
+const centerCrosshair = ref(false)
 // Stage-preview mode: when false (default) buttons behave like normal
 // assets — draggable, no hover/click interaction. When true the canvas
 // turns into a live preview with buttons responding to input.
@@ -593,6 +598,41 @@ const clipGroupConfig = computed(() => {
   }
 })
 
+/** Horizontal + vertical centre-crosshair line configs. Null when
+ *  the toggle is off. Lines span the effective canvas so the centre
+ *  is exactly where layer keyframes default to (canvas.width/2,
+ *  canvas.height/2). Stroke + dash are scaled by `1 / zoom` so they
+ *  stay 1 screen-pixel thick and the dashes stay the same visual
+ *  length at any zoom level. `listening: false` keeps the lines out
+ *  of hit-testing — they're purely a visual guide. */
+const centerCrosshairConfigs = computed(() => {
+  if (!centerCrosshair.value) return null
+  const w = effectiveCanvas.value.width
+  const h = effectiveCanvas.value.height
+  const cx = w / 2
+  const cy = h / 2
+  const z = zoom.value || 1
+  const strokeColor = 'rgba(79, 140, 255, 0.7)'
+  const strokeWidth = 1 / z
+  const dash = [6 / z, 4 / z]
+  return {
+    horizontal: {
+      points: [0, cy, w, cy],
+      stroke: strokeColor,
+      strokeWidth,
+      dash,
+      listening: false,
+    },
+    vertical: {
+      points: [cx, 0, cx, h],
+      stroke: strokeColor,
+      strokeWidth,
+      dash,
+      listening: false,
+    },
+  }
+})
+
 const backgroundConfig = computed(() => {
   // In button-asset edit: checkerboard-ish transparent background so the
   // user sees where the button's canvas ends.
@@ -935,6 +975,20 @@ function isLayerEffectivelyLocked(layer: Layer): boolean {
   return false
 }
 
+/** Clip-track counterpart to `isLayerEffectivelyLocked`. Returns true
+ *  when the ClipTrack's own `locked` is set OR the track sits inside
+ *  a locked group. Used to disable the ci-group's listening + drag so
+ *  a locked clip behaves as if it weren't on the stage — the user
+ *  can't select, drag, or transform its instance. */
+function isClipTrackEffectivelyLocked(trackId: string): boolean {
+  const track = store.scene.clipTracks?.find((t) => t.id === trackId)
+  if (track?.locked) return true
+  for (const g of store.scene.groups ?? []) {
+    if (g.locked && g.childIds.includes(trackId)) return true
+  }
+  return false
+}
+
 function isLayerGhostLocked(layer: Layer): boolean {
   return isLayerEffectivelyLocked(layer) && !showLocked.value
 }
@@ -1280,6 +1334,12 @@ function imageConfig(
  *  events funnel to the outer group and drag/transform apply as a
  *  unit. */
 function clipInstanceGroupConfig(inst: ClipInstance) {
+  // A locked clip track must behave on the stage as if its instance
+  // weren't there at all — clicks pass through, drag is off, and the
+  // transformer can't latch on. `listening: false` on the group
+  // cascades to every descendant (frame rect + inner shapes), so a
+  // single flag covers the selection, drag, and transform paths.
+  const locked = isClipTrackEffectivelyLocked(inst.clipTrackId)
   return {
     id: `ci-group:${inst.id}`,
     x: inst.x ?? 0,
@@ -1287,7 +1347,8 @@ function clipInstanceGroupConfig(inst: ClipInstance) {
     scaleX: inst.scaleX ?? 1,
     scaleY: inst.scaleY ?? 1,
     rotation: inst.rotation ?? 0,
-    draggable: true,
+    draggable: !locked,
+    listening: !locked,
   }
 }
 
@@ -3479,6 +3540,10 @@ function onResizeHandlePointerUp(e: PointerEvent) {
             </template>
           </v-group>
           <v-rect :config="canvasBorderConfig" />
+          <template v-if="centerCrosshairConfigs">
+            <v-line :config="centerCrosshairConfigs.horizontal" />
+            <v-line :config="centerCrosshairConfigs.vertical" />
+          </template>
           <v-rect
             v-for="h in canvasResizeHandles"
             :key="`canvas-resize-${h.edge}`"
@@ -3627,6 +3692,14 @@ function onResizeHandlePointerUp(e: PointerEvent) {
         <PhMaskHappy v-if="!maskPreview" :size="13" />
         <PhPencilSimple v-else :size="13" />
       </button>
+      <button
+        class="zc-btn center-cross-btn"
+        :class="{ active: centerCrosshair }"
+        v-tooltip="centerCrosshair ? t('canvas.centerCrosshairOff') : t('canvas.centerCrosshairOn')"
+        @click="centerCrosshair = !centerCrosshair"
+      >
+        <PhCrosshair :size="13" />
+      </button>
       <button
         class="zc-btn stage-preview-btn"
         :class="{ active: stagePreview }"