fix(windows): preserve backslashes when quoting spawned-process arguments (#5336)

`build_command_line` in the ConPTY backend accumulated runs of backslashes
inside a quoted argument but never emitted them before non-quote characters,
so `C:\Users\me\Folder With Space\README.md` reached the child as
`C:UsersmeFolder With SpaceREADME.md`. Only args routed through the quoted
branch were affected, which matches the reported `zellij edit` failure on
Windows backslash paths containing spaces.

Rewrite the loop to follow `CommandLineToArgvW` rules exactly: n backslashes
not followed by a quote emit literally, 2n+1 escape an embedded quote, and
trailing backslashes are doubled before the closing quote. Add unit tests
for each case, including a regression test for the issue #5293 repro.

0 files changed, 0 insertions, 0 deletions