Ctrl+Q detach broken on WSL2 + Windows Terminal since v0.26.4 (regression)

[ofhtech]

Environment

• agent-deck: v0.26.3 → v0.26.4 (regression)
• OS: Ubuntu 24.04 on WSL2 (Linux 6.6.87.2-microsoft-standard-WSL2)
• Terminal: Windows Terminal (default)
• tmux: 3.4
• Shell: bash

Problem

After upgrading from v0.26.3 to v0.26.4, Ctrl+Q no longer detaches from an attached tmux session back to the agent-deck TUI. The keypress is silently swallowed — the session remains attached with no visible effect.

v0.26.3: Ctrl+Q detach works correctly.
v0.26.4: Ctrl+Q does nothing. Session stays attached.

Suspected cause

v0.26.4 introduced several changes to keyboard handling:

1. extended-keys on added to tmux sessions (Fix #342: enable extended-keys for Shift+Enter in tmux sessions #343) — this changes how tmux forwards modified key sequences to applications
2. Enhanced keyboard protocol detection for Ctrl+Q (fix: detect Ctrl+Q in enhanced keyboard protocol encodings #357) — added ESC[113;5u and ESC[27;5;113~ decoding alongside raw ASCII 17
3. tmux bind-key -n C-q detach-client fallback (Ctrl+Q detach not working (iTerm2 / macOS) — XON/XOFF flow control not cleared on attach PTY #361) — added for iTerm2/macOS XON/XOFF fix

With extended-keys on, Windows Terminal + WSL2 may encode Ctrl+Q in a format that is:

• No longer raw ASCII 17 (byte 0x11) — so the existing bytes.IndexByte(buf, 17) check misses it
• Not one of the two enhanced encodings added in fix: detect Ctrl+Q in enhanced keyboard protocol encodings #357 (ESC[113;5u or ESC[27;5;113~)
• And the tmux bind-key fallback from Ctrl+Q detach not working (iTerm2 / macOS) — XON/XOFF flow control not cleared on attach PTY #361 may not be activating

This is the same class of issue as #361 (macOS/iTerm2) but on a different platform. The fix for #361 may have inadvertently broken the previously-working raw byte path on WSL2.

Steps to reproduce

1. Install agent-deck v0.26.4 on WSL2 (Ubuntu) with Windows Terminal
2. Create or start a session (agent-deck add /path -t "test")
3. Attach to the session (Enter)
4. Press Ctrl+Q — nothing happens, session remains attached
5. Workaround: Ctrl+B d (native tmux detach) still works

Expected behavior

Ctrl+Q should detach from the tmux session and return to the agent-deck TUI, as it did in v0.26.3.

Workaround

Ctrl+B d (standard tmux detach) works reliably.

Related issues

• Ctrl+Q detach not working (iTerm2 / macOS) — XON/XOFF flow control not cleared on attach PTY #361 — Same symptom on iTerm2/macOS, closed in v0.26.4
• fix: detect Ctrl+Q in enhanced keyboard protocol encodings #357 — Enhanced keyboard protocol Ctrl+Q detection
• Fix #342: enable extended-keys for Shift+Enter in tmux sessions #343 — extended-keys on addition to tmux sessions
• Shift key broken (no capital letters) when using Ghostty terminal #397 — Shift key broken on Ghostty (similar keyboard encoding class of issue)