v0.6.30

Add File > Open recording to browse and play a .pgnlog

A new OpenRecordingScreen modal shows a DirectoryTree filtered to directories
and .pgnlog files (rooted at the recordings dir, or cwd), plus a replay-speed
picker. Selecting a file (double-click or Play) calls play_recording, which
swaps in a FileReplayDriver on the chosen path and restarts the exclusive
frame-loop worker — replacing any live serial or previous replay driver. The
File menu gains an "Open recording…" item and an O shortcut.

391 tests green; ruff + mypy clean.