Copilot's TUI turns mouse tracking on itself. Under `strip-mux-only` those DECSETs reached
xterm, which then reported a plain drag to the TUI instead of selecting (only Shift+drag
selected), so Auto Copy and copy-on-select did nothing. This is the failure opencode had and
`strip-mux-and-mouse` was added for: the DECSETs are stripped, a drag is a local selection and
clicks still reach the CLI through the browser's hand-encoded tap (`cliMouseTracking`).
Stripping them also stops xterm from encoding the wheel for the CLI, so
`_shouldForwardWheelToApp` now forwards it as SGR reports while Copilot is tracking the mouse
(the same bytes xterm sent natively, which is what scrolling was verified against). Shift+wheel
stays on local scrollback and a stale flag falls back to PageUp/PageDown.
Tests: the strip flavor for copilot (stripped DECSETs, 3J kept, cliMouseTracking, direct-PTY
untouched) and the wheel gate (forwards while tracking, no other non-claude mode changes).
Devvyn
d732b46797