[FEATURE] Add TemperatureGridSensor.

[Milotrince]

Description

Adds a temperature sensor

Related Issue

Resolves #2456

Motivation and Context

For tactile sensing and other robotics applications.
Other robot learning sims don't have this feature afaik. Genesis would be the first!

How Has This Been / Can This Be Tested?

test_sensors.py

Screenshots (if appropriate):

Screen.Recording.2026-02-24.at.00.51.47.mov

Checklist:

• I read the CONTRIBUTING document.
• I followed the Submitting Code Changes section of CONTRIBUTING document.
• I tagged the title correctly (including BUG FIX/FEATURE/MISC/BREAKING)
• I updated the documentation accordingly or no change is needed.
• I tested my changes and added instructions on how to test it for reviewers.

[duburcqa]

What about making this an example of external sensor plugin ? I think that would be great to show that genesis is modular and extensible for every user specific sensor application. This specific sensor seems to be a good candidate to me!

[Milotrince]

@duburcqa I ran into some issues trying to put the sensor implementation outside of genesis engine in examples/sensors (you can look at my branch temp_sensor_as_plugin):

1. gs types (e.g. gs.tc_int) not yet defined when importing base_sensor

Traceback (most recent call last):
  File "/Users/trinity/Documents/GitHub/genesis/Genesis/examples/sensors/temperature/temperature_grid_sensor.py", line 13, in <module>
    from genesis.engine.sensors import (
  File "/Users/trinity/Documents/GitHub/genesis/Genesis/genesis/engine/sensors/__init__.py", line 1, in <module>
    from . import base_sensor, camera, contact_force, depth_camera, imu, kinematic_contact_probe, raycaster
  File "/Users/trinity/Documents/GitHub/genesis/Genesis/genesis/engine/sensors/base_sensor.py", line 45, in <module>
    class SharedSensorMetadata:
  File "/Users/trinity/Documents/GitHub/genesis/Genesis/genesis/engine/sensors/base_sensor.py", line 51, in SharedSensorMetadata
    delays_ts: torch.Tensor = make_tensor_field((0, 0), dtype=gs.tc_int)
                                                              ^^^^^^^^^
AttributeError: module 'genesis' has no attribute 'tc_int'

2. have to delay array_class import, which is a bit awkward