feat: multi-game port selection — the machine says which game it is on

The runtime tried one port file (game.port) and refused it if the game's
words did not match. Now it tries every *.port in /usr/local/padmode/ports
and /dump/ports (then the single files, the old layout), resetting the port
tables between candidates, and keeps the first whose core sites verify: a
wrong candidate hooks nothing, so trying it is safe, and the port that
verifies names the game (pm_game/pm_version).

The switch log's buttons and names come from the port's switch lines now —
the baked-in King Kong button list and switch_names.inc are gone (the port
lines carry the same ids and names, so King Kong's switch.log is unchanged).

Boot log: each refused candidate says its path and the game/version it
declares; no candidates at all says so; a game update whose port is not
deployed logs the refusal and runs stock.

tests/test_multi_game.py lifts the new code verbatim and compiles it for the
host: selection among candidates, table reset between them, the getdents64
*.port scan (it caught an inverted suffix test and an off-by-one), and the
port-driven switch log. The address-dependent tests need a Linux host (the
port's site addresses are 32 bits; darwin arm64 maps nothing below 4 GiB).

Co-Authored-By: Claude Code <noreply@anthropic.com>

.gitignore

@@ -1,3 +1,4 @@
 # build artifacts
 *.so
 *.o
+__pycache__/