v0.55.0

Added

• uap_scene_save: save a scene without any dialog. Saves the active
  (or a named) loaded scene in place, or to path (Assets/.../Name.unity,
  folders created) with saveAsCopy / overwrite. An untitled scene
  without path is refused up front instead of reaching Unity, which
  would open the Save Scene dialog. There was no save tool before, so
  agents ran the File/Save menu instead -- see below.

Fixed

• uap_editor_execute_menu no longer parks the Editor behind a native
  modal dialog. A live Codex session ran File/Save on an untitled
  scene: Unity opened the native Save Scene dialog inside the call, the
  Editor loop did not tick once until a person closed it (288 s), every
  other uap_* call died "never started" and the panel stopped answering
  permission requests. The menu items measured to open such a dialog
  (File/Save while a scene is untitled, File/Save As...,
  File/Open Scene, File/Build And Run, File/Exit,
  Assets/Import New Asset..., Assets/Import Package/Custom Package...)
  are now refused before they run, with the alternative in the message.
  Build Settings, Project Settings, Preferences and the rest are ordinary
  windows and keep working.
• A main-thread timeout now says when a modal dialog is the cause
  (Windows). For dialogs a third-party menu or tool opens, the timeout
  text names the dialog and says only a person can close it, instead of
  "will finish on its own"; calls issued while it is open fail in 8 s
  with the same note.
• A screenshot returned as text no longer freezes the Editor for
  minutes. Codex hands an MCP result over as one JSON string, base64
  picture included; the tool card's image-path detection ran two regexes
  that were quadratic on such text (measured: 431 s of "not responding"
  for a 498 KB screenshot, 256 s in the live session, shown as "Hold on
  ... EditorUpdatePump.OnEditorUpdate"). The scan is now linear (same
  input: 1 ms) and finds the same paths. Design note:
  docs/design-notes/2026-09-17-modal-menu-and-base64-scan.md.