[sim2 5/6] Add rolling Mid360 acquisition and Point-LIO verification

[Nabla7]

Why do we need this?

An instantaneous ideal cloud is insufficient to exercise a lidar-inertial estimator. Mid360 requires per-return timing, motion history and aligned IMU acquisition.

What is this feature?

Reuses main's Fourier/return-response implementation; retains explicit G1 and Go2 calibrations. Adds rolling raw clouds, corrected clouds, 200 Hz IMU, history invalidation and uniform IMU sampling with 500 Hz Go2 physics. No Point-LIO changes. Calibration/noise are approximations, not a claim of full real-sensor equivalence.

Depends on #4727. Review against pim/refactor/sim2-go2, not main.

Incremental diff: 6 files, +910/-19. Head: 2096bd6dd1d2e0137303ddd4d736596353fa75ad.

How to manually run this

uv run python -c "from dimos.sim2.sensors.lidar.models.mid360 import Mid360; r=Mid360(calibration='g1').scan(0.0, 0.1); print(r.directions.shape, r.offsets[[0,-1]], sorted(set(r.lines)))"
# Expected: 20,000 directions, 0..0.099995 s offsets, channels 0..3.
# The procedural Go2 blueprint in 6/6 exercises this live.

Verification

Both calibration tests and the actual native Point-LIO stage canary pass with and without a 640x480 camera. 10-second measurement, 0.6 m motion, zero dropped scans/IMU. Not a ten-minute or complex-scene performance guarantee. Build pointlio_native or set SIM2_POINTLIO_BINARY for that optional canary.

Draft review: final commits use [skip ci]; local evidence is recorded instead of starting the long CI matrix. Hardware changes still need physical-robot review before merge.

Which issue(s) does this PR close?

None. This is a dependent migration stack, not an independent replacement for the upstream connection work.

Earlier layers:

• Control integration: [sim2 prerequisite] Reconcile connection modules with coordinator control and estop #4723
• Emulator core: [sim2 1/6] Extract shared MuJoCo world, device client and sensor workers #4724
• G1: [sim2 2/6] Migrate G1 to one connection with GR00T and standalone SONIC #4725
• Arms: [sim2 3/6] Migrate xArm and Piper blueprints through public arm connections #4726
• Go2: [sim2 4/6] Drive Go2 through GO2Connection and its existing walking policy #4727

Checklist

• I have read and approved the CLA.