dosforge 0.9.51

dosforge 0.9.51 — Windows GUI: Combobox wheel + focus polish

Quality-of-life fix for the Windows GUI (Linux GUI benefits too).

What's fixed

In the New Disk view, ttk.Combobox dropdowns no longer behave
weirdly on Windows:

• Wheel-over-dropdown now scrolls the page. Previously, rolling the
  mouse wheel over (or past) any dropdown — DOS Version, Disk Format,
  BIOS preset, etc. — would either cycle the dropdown's value or "get
  stuck" inside it instead of scrolling the form. Tk's default
  <MouseWheel> class binding on TCombobox is now removed, so
  the page-level scroll handler always wins.
• Clicking outside a dropdown releases focus. Previously, after
  picking a value from (e.g.) the DOS Version dropdown, focus stayed on
  that combobox even after clicking another field — its highlight ring
  lingered and subsequent wheel events could still mutate its value.
  Now any click outside a Combobox transfers focus to the toplevel, the
  same way a native Win32 ComboBox loses focus when you click off it.
• Selecting a value defocuses immediately. As soon as
  <<ComboboxSelected>> fires, selection_clear() runs and focus
  moves to the toplevel — the visible highlight no longer survives the
  dropdown closing.

Scope

Only src/dosforge/_gui/widgets.py (new apply_combobox_polish helper),
src/dosforge/_gui/__init__.py (wires the helper into the Tk root
during DosForgeGUI.__init__), and src/dosforge/_gui/create_view.py
(adds <<ComboboxSelected>> defocus on every _Combo instance) were
touched. The TUI, CLI, and disk/boot pipelines are unaffected.

Tests

New tests/test_gui_combobox_polish.py smoke-tests the helper against a
hidden Tk root (skips cleanly on truly headless runners). All
existing targeted-sweep tests still pass.

Upgrade

No data-format changes. Drop-in replacement for v0.9.50.