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>

crates/script/src/lib.rs

@@ -0,0 +1,64 @@
+//! # effectcraft-script (L4)
+//!
+//! Scripting with an After Effects-style object model, on the boa JavaScript engine (the one the
+//! expressions use). Scripts written for After Effects' documented scripting API mostly run
+//! unchanged:
+//!
+//! ```text
+//! app.beginUndoGroup("Build");
+//! var comp = app.project.items.addComp("Main", 1920, 1080, 1, 10, 30);
+//! var solid = comp.layers.addSolid([1, 0, 0], "Red", 1920, 1080, 1);
+//! solid.property("ADBE Transform Group").property("ADBE Position").setValueAtTime(0, [0, 540]);
+//! solid.Effects.addProperty("ADBE Gaussian Blur 2").property("Blurriness").setValue(20);
+//! app.endUndoGroup();
+//! ```
+//!
+//! * **Object model** (`prelude.js`): `app` (project, open/newProject, undo groups,
+//!   `executeCommand`/`findMenuCommandId`, `scheduleTask`), `Project`, `ItemCollection`,
+//!   `CompItem`/`FootageItem`/`FolderItem`, `LayerCollection`, `AVLayer`/`TextLayer`/
+//!   `ShapeLayer`/`CameraLayer`/`LightLayer`, `PropertyGroup`/`Property` (values, keyframes,
+//!   eases, expressions), `MaskPropertyGroup`, `TextDocument`, `Shape`, `KeyframeEase`,
+//!   `MarkerValue`, `RenderQueue`/`RenderQueueItem`/`OutputModule`, `ImportOptions`, `File`/
+//!   `Folder`, `$`, `alert`/`writeLn`, and the enums (`BlendingMode`, `KeyframeInterpolationType`,
+//!   `TrackMatteType`, `LightType`, `ParagraphJustification`, `PropertyValueType`…).
+//! * **Edits are engine commands**: every mutating call runs a command through
+//!   [`Session::execute`](effectcraft_engine::Session::execute), so it is undoable, journaled
+//!   and identical to the UI's action; `app.beginUndoGroup`/`endUndoGroup` fold everything in
+//!   between into one undo step.
+//! * **Match names** ([`matchnames`]): After Effects' documented match names for our properties
+//!   and effects (`ADBE Transform Group`, `ADBE Position`, `ADBE Gaussian Blur 2`…).
+//! * **Security**: scripts can import/open/save projects and render, but `File` reads are limited
+//!   to the project's folder and writes (and the network) are off unless Preferences ▸ Scripting
+//!   & Expressions ▸ Allow Scripts to Write Files and Access Network is on.
+//!
+//! Entry points: [`install`] sets [`Session::script`](effectcraft_engine::Session::script), which
+//! the `script.run` command, File ▸ Scripts ▸ Run Script File… (`.jsx`/`.js`), the Script Console
+//! panel, `effectcraft-cli script` and the MCP `run_script` tool use.
+
+#![recursion_limit = "256"]
+
+pub mod matchnames;
+mod model;
+mod runtime;
+
+use effectcraft_engine::{ScriptRequest, Session};
+
+pub use runtime::{Outcome, ScriptError, run};
+
+/// The [`effectcraft_engine::ScriptRunner`] this crate provides.
+pub fn runner(s: &mut Session, req: &ScriptRequest) -> serde_json::Value {
+    run(s, req).to_json()
+}
+
+/// Enable scripting on a session.
+pub fn install(s: &mut Session) {
+    s.script = Some(runner);
+}
+
+/// Run `code` as a one-off script named `name`.
+pub fn run_code(s: &mut Session, code: &str, name: &str) -> Outcome {
+    run(s, &ScriptRequest { code, name, console: false })
+}
+
+#[cfg(test)]
+mod tests;