fix(fish): trigger prompt repaint when Enter is pressed with pager open

[Copilot]

When the fish completion pager is open and the user presses Enter to execute a command, OMP was not refreshing the prompt — leaving it stale (e.g. showing the old pwd after cd).

Root cause

_omp_enter_key_handler had an early-return path for paging mode that called execute and returned without setting _omp_new_prompt = 1. On the next fish_prompt call, OMP saw the flag as 0 and echoed the cached prompt unchanged.

# Before — missing prompt refresh in paging-mode path
function _omp_enter_key_handler
    if commandline --paging-mode
        commandline --function execute
        return  # _omp_new_prompt never set to 1
    end
    ...
end

Fix

The paging-mode branch now mirrors the normal execution path:

if commandline --paging-mode
    set --global _omp_new_prompt 1
    set --global _omp_tooltip_command ''
    _omp_cleanup_stream
    if test $_omp_transient_prompt = 1
        set --global _omp_transient 1
        commandline --function repaint
    end
    commandline --function execute
    return
end

This ensures tooltip state, streaming cleanup, transient prompt handling, and the repaint flag are all consistent regardless of whether execution was triggered from the pager.

[TheFurnace]

I built and tested this branch on my machine at it appears to resolve the issue. My repro steps from the original issue no longer cause the bug.