### System details

- Omarchy: 4.0.0-1 - Hyprland: 0.56.2 (Lua config) - Kernel: 7.1.8-arch1-3 - fcitx5: 5.1.21-1 (+ fcitx5-chewing) - Terminal: ghostty 1.3.1

### What's wrong?

With the default `kb_options = "compose:caps,shift:both_capslock_cancel"`, the left Shift key cannot be used as a modifier-only trigger to toggle Chinese/English in fcitx5. A quick tap of the physical Shift while the Chinese input method is active does nothing.

The same config works fine with keys injected through a virtual keyboard (wtype), which is why this is easy to miss.

### Root cause

`shift:both_capslock_cancel` defines the Shift keys with an XKB ALPHABETIC two-level mapping:

 ```

key <LFSH> {[ Shift_L, Caps_Lock ], type[group1]="ALPHABETIC" };

 ```

fcitx5 key_trace (`fcitx5 --verbose key_trace=5`) shows the physical Shift press/release pair:

 ```

 PRESS:   Key(Shift_L states=0)  rawKey: Key(Shift_L states=16)  keycode: 50
 RELEASE: Key(Shift+Caps_Lock states=1)  rawKey: Key(Shift+Caps_Lock states=1)  keycode: 50

 ```

The release event's keysym is `Caps_Lock`, not `Shift_L`. fcitx5's modifier-only trigger handling (`Instance::canAltTrigger` / trigger keys, instance.cpp keyHandlers release path) matches release via
`Key::isReleaseOfModifier(lastKeyPressed)`, which fails when the release keysym differs. So the toggle never fires for a physical Shift tap.

### Expected behavior

Tapping left Shift while Chinese input is active should toggle to English (and back), like it does on every other fcitx5 setup.

### Workaround (verified)

Override `kb_options` in `~/.config/hypr/input.lua`:

```lua
hl.config({
  input = {
    kb_options = "compose:caps",
  },
})
 ```

 After hyprctl reload, the release keysym becomes Shift+Shift_L and the toggle works.

### Impact / related

 - Affects any fcitx5 user relying on a Shift-based toggle (fcitx5's default AltTriggerKeys is Shift_L), i.e. basically all Chinese/Japanese input users on Omarchy 4.0.
 - #7255 reports another bug from the same option (Caps Lock stuck ON after the Quattro migration).
 - #7346 reports the same symptom (Shift cannot toggle Chinese/English) but with a different root cause (Hyprland 0.56.2 dropping modifier release events); both may affect 4.0 users.
 - Suggestion: drop shift:both_capslock_cancel from the default kb_options, or pick a Caps-Lock-home that doesn't rewrite the Shift keysym (e.g. caps:escape with compose elsewhere).