feat(04-04): add UpdateParamsCommand + BlockInspector module

- UpdateParamsCommand with execute/undo for color/speed/direction/length
- Uses module-level currentShowId (not this._showId) matching existing pattern
- BlockInspector renders compact strip with animation label, color swatch,
  speed input, direction select, length input, and remove button
- Color change committed on 'change' event (not 'input') to avoid command flood
- _onDelete callback wired to remove button for app.js to handle

lightsync/frontend/timeline/commands.js

@@ -88,6 +88,27 @@ export class ResizeBlockCommand {
     }
 }
 
+// ── UpdateParamsCommand ──────────────────────────────────────────────────────
+
+export class UpdateParamsCommand {
+    constructor(tracks, block, oldParams, newParams) {
+        this.tracks = tracks;
+        this.block = block;
+        this.oldParams = { ...oldParams };  // shallow copy
+        this.newParams = { ...newParams };  // shallow copy
+    }
+
+    execute() {
+        Object.assign(this.block.params, this.newParams);
+        syncBlock(currentShowId, this.block.device_id, this.block, 'PATCH');
+    }
+
+    undo() {
+        Object.assign(this.block.params, this.oldParams);
+        syncBlock(currentShowId, this.block.device_id, this.block, 'PATCH');
+    }
+}
+
 // ── DeleteBlockCommand ───────────────────────────────────────────────────────
 
 export class DeleteBlockCommand {