M14.4: scripting with an After Effects-style JavaScript object model

New crate effectcraft-script (L4): boa runtime with app/Project/CompItem/
Layer/PropertyGroup/Property/TextDocument/MarkerValue/RenderQueue/File
object model over engine commands (undoable, undo groups), AE match-name
table, file/network security gate. Entry points: script.run command,
File > Scripts > Run Script File (.jsx/.js), Window > Script Console,
effectcraft-cli script, MCP run_script. Engine: project.delete/duplicate,
prop.renameGroup/setGroupEnabled/removeGroup/duplicateGroup/moveGroup.

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

apps/effectcraft-web/src/lib.rs

@@ -105,8 +105,8 @@ fn query_flag(name: &str) -> bool {
     web_sys::window().and_then(|w| w.location().search().ok()).and_then(|s| web_sys::UrlSearchParams::new_with_str(&s).ok()).is_some_and(|p| p.has(name))
 }
 
-/// A session wired for the browser: media decoding from memory, expressions, Render Queue export
-/// to downloads.
+/// A session wired for the browser: media decoding from memory, expressions, scripting, Render
+/// Queue export to downloads.
 pub fn session() -> Session {
     let pool = Arc::new(effectcraft_media::MediaPool::new());
     Session {
@@ -115,6 +115,7 @@ pub fn session() -> Session {
         importer: Some(Arc::new(files::WebImporter { pool })),
         expr: Some(Arc::new(effectcraft_expr::Expressions)),
         expr_check: Some(effectcraft_expr::check_syntax),
+        script: Some(effectcraft_host::script::runner),
         exporter: Some(Arc::new(effectcraft_host::FileExporter { sink: Some(files::export_sink()) })),
         ..Default::default()
     }