CMP-7: Essential Graphics controls, master properties, .ectemplate templates, Responsive Design — Time

Comps expose controls (properties typed as text/color/slider/checkbox/point/angle/dropdown,
Media Replacement, groups, comments); precomp layers get an Essential Properties group whose
edits override per instance (Push to Comp / Revert); templates export/import as an open ZIP
(manifest.json + project subset + media + poster). Stretched precomps keep protected regions
at their original speed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/gpu/src/tests.rs

@@ -100,6 +100,7 @@ impl Scene {
             missing: false,
             sequence: vec![],
             color_profile: None,
+            ..Default::default()
         };
         let fid = self.p.add_item("Pattern", Label::Lavender, None, ItemKind::Footage(f));
         build::layer(&mut self.p, &self.comp, "Pattern", LayerSource::Footage { item: fid }, (w, h), None)