Re-enter raw mode after piped input ends

[anandghegde]

Fixes #415

I could reproduce this on macOS with node 26: node -e 'process.stdout.write(JSON.stringify({"a":1}))' | fx renders, but keys get echoed at the bottom and nothing responds. It's a race, which is probably why it works on some machines.

Cause: node saves the terminal settings (termios) when it starts and restores them when it exits (ResetStdio in node). fx starts the TUI before node has exited, so bubbletea puts the terminal in raw mode, and then node's exit puts it back into canonical + echo mode. cat file | fx never hits this because cat doesn't touch the terminal.

The same thing happens with any producer that saves and restores terminal state. For example, this Python script breaks fx every time:

import termios, sys, time
a = termios.tcgetattr(2)          # save at startup
sys.stdout.write('{"a":1}'); sys.stdout.flush()
time.sleep(0.5)
termios.tcsetattr(2, termios.TCSANOW, a)  # restore at exit

Fix: the producer's stdout only reaches EOF after the process has exited, so after the restore. On eofMsg, fx now opens /dev/tty and puts it back into raw mode (term.MakeRaw, the same call bubbletea uses). If the terminal is already raw this does nothing. On exit, bubbletea still restores the original state it saved, so the shell is left normal. If /dev/tty can't be opened (e.g. on Windows), it's a no-op.

Testing: I ran fx inside a pty from a small Python harness. The harness answers fx's OSC 11 and cursor-position queries, checks the tty's ICANON/ECHO flags 2s after start, then sends q:

producer	before	after
node -e ...	18/20 runs broken (ICANON+ECHO on, q ignored)	20/20 OK, q exits
termios save/restore script above	3/3 broken	3/3 OK
echo '{"a":1}'	OK	OK

stty -a after fx exits shows icanon echo, so the terminal is restored properly. go test ./... passes, and GOOS=windows / GOOS=linux builds succeed.

This doesn't address the leaked ^[]11;rgb:...^[[48;1R seen on Ubuntu. That's when node's exit lands during the startup background-color query.

Implemented with Claude Code; I reviewed and tested the change.

🤖 Generated with Claude Code

https://claude.ai/code/session_01MA8JGs7pCoXFL2W6jEJ8sD