Scripts: the Startup and Shutdown folders run at launch and quit

Scripts in Scripts/Startup and Scripts/Shutdown in the settings folder
were never run. The desktop and web apps now run the Startup scripts at
launch, before a project opens, and the desktop app runs the Shutdown
scripts as it quits, after the project is closed. Each folder runs in
alphabetical order with case ignored, and files larger than 16 MiB are
not run. A Startup script that fails is reported in a toast and in the
log, a Shutdown script that fails is reported in the log, and the next
one still runs.

A Startup script that waits in a modal dialog goes on when the dialog
closes, while the next scripts run. A Shutdown script's dialogs close
as if canceled. With the settings folder on disk, each script runs as
its file, so #include, $.fileName and $.evalFile resolve against the
script's own folder.

The new commands file.runStartupScripts and file.runShutdownScripts
return the scripts that ran, those still waiting in a dialog, and those
that failed. Like script.run, both are refused in confined automation
sessions, in batches and in script steps, which now read one list of
script commands (RUNS_SCRIPTS). The list also holds window.scriptPanel
and window.restoreScriptPanels, which run ScriptUI panel scripts and
were not refused on main either. The apps still call
window.restoreScriptPanels at launch. plugins.md, scripting-parity.md,
gaps.md, target-app-parity.md and agents.md describe the folders. Each script
still runs in its own global scope, so a Startup script's variables are
not available to later scripts.

docs/plugins.md

@@ -15,7 +15,7 @@ Guide):
 | Scripts folder: its scripts are listed in File ▸ Scripts | `Scripts/` in the settings folder (File ▸ Scripts ▸ Install Script File… copies a script there), listed in File ▸ Scripts with the bundled samples | Same |
 | File ▸ Scripts ▸ Run Script File… (`.jsx`, `.jsxbin`) | `.jsx` / `.js` | Gap: `.jsxbin` (an undocumented binary encoding) |
 | ExtendScript preprocessor directives (`#include`, `#target`, `#targetengine`) | `#include` / `//@include` / `#includepath` inline files relative to the script (once each, depth-limited, file gate applies); `#target`, `#targetengine`, `#strict` are ignored | Same |
-| `Scripts/Startup` and `Scripts/Shutdown`: run in alphabetical order when the app starts and quits | Not run | Gap |
+| `Scripts/Startup` and `Scripts/Shutdown`: run in alphabetical order when the app starts and quits | `Scripts/Startup/` and `Scripts/Shutdown/` in the settings folder, in alphabetical order (case ignored): the Startup scripts run at launch before a project opens, and the Shutdown scripts run as the desktop app quits, after the project is closed. A Startup script that fails is reported in a toast and in the log, a Shutdown script that fails is reported in the log, and the next script still runs | Partial: each script runs in its own global scope, so variables and functions a Startup script defines are not available to later scripts; a Startup script's modal dialog stays open while the next scripts run and the app starts; a Shutdown script's modal dialogs close as if canceled; the web app runs no Shutdown scripts |
 | `Scripts/ScriptUI Panels`: listed at the bottom of the Window menu, dockable like the app's own panels, `this` is the panel | `Scripts/ScriptUI Panels/` in the settings folder (File ▸ Scripts ▸ Install ScriptUI Panel… copies one there), listed at the bottom of the Window menu, docked like any panel, `this` is the panel; the panels open when the app quits open again at the next launch | Same. Where a panel was docked isn't kept: workspace layouts aren't saved between launches |
 | Keyboard shortcuts for scripts (the Keyboard Shortcuts editor lists the scripts of the Scripts folder) | Shortcuts bind to commands and menu entries; the File ▸ Scripts and Window menu entries of scripts aren't offered | Gap |
 | Running a script from the command line (`afterfx -r script.jsx`) | `effectcraft-cli script`, the control channel's and MCP's `script.run` | Same purpose, other entry points |
@@ -38,6 +38,10 @@ journaled and the same as the UI's action. The `effectcraft-script` crate's docs
   file.jsx`, or `script.run {code, name}` over the control channel and MCP.
 * Install one: File ▸ Scripts ▸ Install Script File… (or copy it into `Scripts/` in the settings
   folder). It is listed in File ▸ Scripts at once (After Effects asks for a restart).
+* Run one at every launch or quit: copy it into `Scripts/Startup/` or `Scripts/Shutdown/` in the
+  settings folder. These scripts are not listed in File ▸ Scripts. `file.runStartupScripts` and
+  `file.runShutdownScripts` run them and return `{ran, waiting, failed}`; the desktop app calls them at
+  launch and quit, and the web app calls `file.runStartupScripts` at launch.
 * `file.scripts.list` lists installed and bundled scripts and panels; `file.runScript {name}` runs
   one; `file.uninstallScript {name}` removes an installed one.