Fix provided by @jcollie 

The swift `open_config` action was triggering an allocation error
`error(gpa): Allocation size 41 bytes does not match free size 40.`.

> A string that was created as a `[:0]const u8` was cast to `[]const u8`
and then freed. The sentinel is the off-by-one.

@jcollie 

For full context, see
https://discord.com/channels/1005603569187160125/1420367156071239820

Co-authored-by: Jeffrey C. Ollie <jcollie@dmacc.edu>

Fixes #2473

This commit changes `ghostty_surface_ime_point` to return a full rect
with the width/height calculated for the preedit.

The `firstRect` function, which calls `ghostty_surface_ime_point` was
previously setting the width/height to zero. macOS didn't like this. We
then changed it to just hardcode it to width/height of one cell. This
worked but made it so the IME cursor didn't follow the preedit.

Renamed the ghostty_quick_terminal_size_u to
ghostty_quick_terminal_size_s and moved the QuickTerminalSize file to
the Ghostty folder as requested.

Applying the feedback given by @pluiedev to use an enum to specify the
type of quick terminal size configuration given (pixels or percentage).
Updated the Swift code to work with the enum as well.

Added C bindings for the already existing quick-terminal-size
configuration. Created a new QuickTerminalSize struct to hold these
values in Swift. Updated the QuickTerminal implementation to use the
user's configuration if supplied. Retains defaults. Also adds support to
customize the width of the quick terminal (height if quick terminal is
set to right or left).

- Add mode (`this`/`other`) parameter to `close_tab` keybind/apprt action.
- Keybinds will default to `this` if not specified, eliminating backward
  compatibility issues (`keybind=x=close_tab` === `keybind=x=close_tab:this`).
- Remove `close_other_tabs` keybind and apprt action.

Supporting command line, file menu and keybindings.
Default mac shortcut of `super + alt + o` (other)

Not able to test on Linux so excluding `close_other_tabs` from `gtk` for now
make a default short cut for close other tabs