The scene view and the animation preview share one camera, the three form dialogs one base, and keys are found through one set of helpers (#85)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/editor/state.ts

@@ -1,4 +1,5 @@
-import type { KeyClipboard, KeyRef } from '../core/commands/animationCommands';
+import type { KeyClipboard } from '../core/commands/animationCommands';
+import { findKey, findTrack, hasKey, type KeyRef, sameKey } from '../core/model/animation';
 import { type Command, CommandError } from '../core/commands/Command';
 import { CommandStack } from '../core/commands/CommandStack';
 import type { Asset, SceneAsset } from '../core/model/Asset';
@@ -126,8 +127,7 @@ export function graphSelection(
  */
 export function trackSelection(assetId: string, keys: readonly KeyRef[], trackId?: string): Selection {
   const unique: KeyRef[] = [];
-  for (const key of keys)
-    if (!unique.some((k) => k.trackId === key.trackId && k.frame === key.frame)) unique.push(key);
+  for (const key of keys) if (!hasKey(unique, key)) unique.push(key);
   const last = unique[unique.length - 1];
   const row = trackId ?? last?.trackId;
   return row ? { kind: 'track', assetId, trackId: row, keys: unique } : null;
@@ -495,10 +495,8 @@ export class EditorState {
       if (!asset) this.select(null);
       else {
         // A key that moved or died leaves the selection; a row that died takes its keys with it.
-        const alive = s.keys.filter((key) =>
-          asset.tracks.some((t) => t.id === key.trackId && t.keys.some((k) => k.frame === key.frame)),
-        );
-        const rowAlive = asset.tracks.some((t) => t.id === s.trackId);
+        const alive = s.keys.filter((key) => findKey(asset, key));
+        const rowAlive = findTrack(asset, s.trackId) !== undefined;
         if (alive.length !== s.keys.length || !rowAlive)
           this.select(
             trackSelection(s.assetId, alive, rowAlive ? s.trackId : undefined) ?? {
@@ -525,6 +523,11 @@ export class EditorState {
     return findAssetOf(this.project, s.assetId, 'animation')?.id ?? null;
   }
 
+  /** The timeline row the selection is about; undefined when it is about something else. */
+  get selectedTrackId(): string | undefined {
+    return this.selection?.kind === 'track' ? this.selection.trackId : undefined;
+  }
+
   /** The keys picked in the Animation tab, none when the selection is about something else. */
   get selectedKeys(): KeyRef[] {
     return this.selection?.kind === 'track' ? this.selection.keys : [];
@@ -627,7 +630,7 @@ export function sameSelection(a: Selection, b: Selection): boolean {
       a.assetId === b.assetId &&
       a.trackId === b.trackId &&
       a.keys.length === b.keys.length &&
-      a.keys.every((key, i) => key.trackId === b.keys[i]!.trackId && key.frame === b.keys[i]!.frame)
+      a.keys.every((key, i) => sameKey(key, b.keys[i]!))
     );
   if (a.kind === 'annotation' && b.kind === 'annotation')
     return (