#760: $.evalFile and a minimal BridgeTalk host identification

Problem: `$.evalFile` always threw, and `typeof BridgeTalk` was
`undefined`, so frameworks such as DuAEF failed during initialisation
when they load their modules or ask which application they run in.

Fix: `$.evalFile(file[, timeout])` evaluates a script file in the global
scope and returns its last value. Relative paths resolve against the
folder of the file being evaluated (the running script's for the
outermost call, else the project's); reads follow the same file gate,
16 MiB size cap and 32-deep nesting limit as `#include` (#759, shared
`scriptfile.rs`), and the bracket-depth check runs before parsing.
`BridgeTalk` names the host honestly (`appName` "effectcraft", its
version, `appSpecifier`, `isRunning` / `getSpecifier` / `getStatus` /
`getTargets` for ourselves only); `send()` throws a clear "not
supported" error instead of messaging other applications.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/scripting-parity.md

@@ -19,6 +19,7 @@ our own scripts; no real-world script library has been run against both apps.
 | Expression editing | Inline field, error bar, pick whip, Expression Language menu, external editors | Inline field that grows, error bar, pick whips (property and value), language menu | partial | External editor support (#364) |
 | Expression performance | Cached, multi-frame | Per-thread boa contexts | unknown | No benchmark |
 | Scripting object model | `app`, `Project`, items, layers, properties, keys, eases, render queue, `TextDocument`, `Shape`, markers, `File`/`Folder`, `Socket`, `app.settings` | Same classes, edits run through undoable engine commands; match names table | good | `crates/script` tests (≈ 10 test files) |
+| `$.evalFile`, `BridgeTalk` | Evaluate another script file; identify the host application and message other Adobe applications | `$.evalFile` evaluates a file relative to the calling file (nested at most 32 deep, under the scripts' file gate) and returns its last value; `BridgeTalk` names the host honestly (`appName` `effectcraft`, its version); messaging other applications throws "not supported" | partial | `tests_evalfile.rs` (#760); no inter-application messaging |
 | ScriptUI | Dialogs, palettes, dockable panels, resource strings, `onDraw` / ScriptUIGraphics | Same, dockable panels reopen at launch | good | `ui_scriptui`, `tests_ui*` |
 | Scripts menu, ScriptUI Panels folder | yes | yes | same | [plugins.md](plugins.md) |
 | Startup / Shutdown folders | yes | not run | missing | plugins.md |