Replace the StartPty stub with a real ConPTY implementation:
CreatePipe + CreatePseudoConsole + PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE
+ CreateProcess. Pagers and external diff tools now get real terminal
behavior instead of being handed pipes.
One Windows-specific quirk worth flagging: ConPTY does not EOF the
output pipe when the child exits; conhost keeps it alive until
ClosePseudoConsole is called explicitly. A background waiter goroutine
calls ClosePseudoConsole as soon as proc.Wait returns, so callers see
EOF on outRead — restoring the Unix master-fd-EOFs-when-slave-closes
semantics they depend on.
The ErrPtyUnsupported sentinel and the no-pty fallback in newPtyTask
are gone now that both platforms have a real implementation.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Move the pty master behind a small interface (Read/Write/Close/Resize),
and push the actual startup into a platform-specific StartPty function
in pkg/commands/oscommands. The Unix implementation still uses
creack/pty; the Windows implementation is a stub that returns
ErrPtyUnsupported, at which point newPtyTask falls back to a plain cmd
task — matching the existing Windows behavior.
The primitive lives in oscommands rather than pkg/gui because the
cmd_obj_runner pty handler (also in oscommands) is going to consume it
too, and tasks → oscommands is the existing dependency direction.
Same observable behavior on every platform; this just carves out a seam
for a real ConPTY implementation on Windows.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
