From ba9bedeef35a482081d4ab9fcf3fd2635bcd7133 Mon Sep 17 00:00:00 2001
From: yan <yan@localhost>
Date: Fri, 9 Oct 2026 14:10:11 +0300
Subject: [PATCH] chore: start PTY-based terminal

Refs #5. Replace the pipe-based shell with a real pseudo-terminal so
interactive programs render and Ctrl-C reaches the foreground process
group.

Plan, per the issue:
- open a PTY via posix_openpt/grantpt/unlockpt and replace the three
  pipes in TerminalSession
- parse at least CR, BS, LF and ANSI SGR so ls --color and git diff
  render, behind a protocol so the parser stays unit-testable
- send TIOCSWINSZ on panel resize
- forward SIGINT to the foreground process group instead of writing
  0x03 to a pipe the shell does not read as a signal

Keeping the existing pipe implementation as the fallback until the PTY
path is verified against an interactive program.