revert hyundai canfd torque to stock; park-publish keepalive; dashcam idle on park

Three independent changes bundled together.

Revert hyundai canfd steering torque limits to comma stock defaults
(270 / 2 / 3 / 112) in both panda safety and openpilot CarControllerParams.
The 270->324 bump caused overcorrection on turns and weaving on straights.
Web research turned up no public reports of any 4th gen Tucson NX4 owner
bumping STEER_MAX — the documented Tucson tuning effort is entirely on
lateralTuning (latAccelFactor ~2.9-3.1, friction ~0.095), not the cap.
hoomoose's EV6/Ioniq 5 PR #25723 is the canonical "raise STEER_MAX
without dropping latAccelFactor causes overcorrection" data point — and
even that change was reverted upstream. Right next move for this car is
to tune latAccelFactor / friction, not the torque ceiling.

plannerd: keep publishing longitudinalPlan at the normal cadence in park,
but skip update() compute. Skipping publishes entirely caused
longitudinalPlan to time out the alive flag at controlsd, which fired a
real commIssue ("not_alive") on park->drive. Stale published values are
fine because controlsd's own park short-circuit ignores the
longitudinalPlan content while parked. Also gate publish_ui_plan on
not-parked: it reads longitudinal_planner.a_desired_trajectory_full
which is only set inside update(), so calling it without a prior update
crashes plannerd with AttributeError (which fires "Process Not Running"
on screen). uiPlan is UI-only, not on controlsd's commIssue check list,
so going silent in park is fine.

frogpilot_process: same idea — keep publishing frogpilotPlan in park to
keep alive, skip the heavy update() compute.

dashcamd: close the trip immediately on gear shift to PARK (was: 10-min
idle timer before close). User wants the dashcam idle in park and a
fresh trip on every drive engagement; brief drive-thru / fuel-stop
across-trip continuity isn't valued.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

panda/board/safety/safety_hyundai_canfd.h

@@ -1,16 +1,11 @@
 #include "safety_hyundai_common.h"
 
 const SteeringLimits HYUNDAI_CANFD_STEERING_LIMITS = {
-  // CLEARPILOT: bumped from comma defaults (270/2/3/112) by ~20% so this Tucson HDA2
-  // can hold modest curvature in place. Mirrors the rate-limit shape comma uses for
-  // its non-CAN-FD high-torque HKG default (384/3/7). Must stay in lockstep with
-  // STEER_MAX in selfdrive/car/hyundai/values.py — panda enforces independently and
-  // will reject larger commands if openpilot's value exceeds this.
-  .max_steer = 324,
-  .max_rt_delta = 134,
+  .max_steer = 270,
+  .max_rt_delta = 112,
   .max_rt_interval = 250000,
-  .max_rate_up = 3,
-  .max_rate_down = 5,
+  .max_rate_up = 2,
+  .max_rate_down = 3,
   .driver_torque_allowance = 250,
   .driver_torque_factor = 2,
   .type = TorqueDriverLimited,