byd: fix canError ("Unknown Vehicle Variant") from strict parser alive checks

Explicit parser frequencies made canValid=False when state-dependent
messages are absent (PCM_BUTTONS is event-driven; MPC_LKAS_CMD/ACC_CMD
only flow when stock ADAS is active), tripping EventName.canError.

- Alive-check only control-critical messages, at a conservative 10Hz
  (1s timeout): ESC, BRAKE_APPLIED, PEDAL, STEER_MODULE, STEERING_TORQUE,
  DRIVE_STATE, ACC_HUD_ADAS
- Parse-but-don't-alive-check (nan) the rest: STALKS, METER_CLUSTER,
  MPC_LKAS_CMD, ACC_CMD
- PCM_BUTTONS is parsed on both pt and cam parsers (bus assignment is
  harness dependent); MADS reads LKAS_ON_BTN from whichever bus sees it

Verified: canValid=True with idle stock ADAS, LKAS button events work
from either bus, canValid stays True throughout.

.serena/.gitignore

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+/cache
+/project.local.yml