Automatchmaker hangs at character select on Match 2+

[ScavieFae]

Description

Running nojohns auto (automatchmaker), Match 1 completes successfully but Match 2 gets stuck at character select. Dolphin launches, WebSocket connects, "Starting game 1" is logged, but the game never progresses past the CSS. Requires Ctrl+C to exit.

Reproduction

1. Run automatchmaker: nojohns auto phillip
2. Match 1 completes normally (win/loss recorded, wager settled)
3. Match 2: matchmaking succeeds, wager locks, Dolphin launches
4. Hangs indefinitely at character select screen

Data from Session

--- Match 2 ---
14:54:51 [INFO] Matched! Opponent: SCAV#382
[WAGER] LOCKED -- 0.02 MON pot (ID: 2)
14:54:58 [INFO] Launching netplay...
14:54:58 [INFO] Random character: KIRBY
14:55:00 [INFO] Match streamer (WebSocket) started
14:55:00 [INFO] Starting game 1
<hangs here — never progresses past character select>

Match 1 completed fine (1-0 record, wager settled). Character was KIRBY (not Sheik/ICs, so not the known gotcha #20).

Environment

• macOS, Apple M3 Pro
• Slippi Dolphin (netplay)
• This machine (Moltbook / ScavieFae's machine)

Likely Cause

CLAUDE.md gotcha #19: --dolphin-home tradeoffs on multi-match sessions. On match 2+, Dolphin may get stuck at name selection when reusing the same home directory, or fail without it. The menu navigator doesn't recover from this state.

Possible contributing factors:

• Dolphin state leaking between matches (gotcha Headless mode not supported with Slippi Dolphin #16 — libmelee socket/temp state)
• The subprocess-per-match pattern in test scripts exists to avoid exactly this, but the automatchmaker may not be using it

Suggested Investigation

• Check if auto mode spawns a fresh subprocess per match or reuses the same process
• Check --dolphin-home behavior on match 2+ (is Slippi account state stale?)
• Consider adding a timeout/watchdog for the character select phase (similar to the console.step() watchdog in gotcha Add indexer for full match history queries #17)

cc @scav — this is in games/melee/netplay.py / nojohns/cli.py territory