Add warning banner to Redux Robotics third-party CAN devices (#3154)

## Summary
Adds a warning banner to the Redux Robotics section in the third-party CAN devices documentation to inform users that the company is shutting down.

## Changes
- Added warning banner noting Redux Robotics shutdown
- Clarifies that devices remain legal for FRC use
- Notes that software support will be provided for 2026 season
- Mentions no new hardware will be available

This keeps the documentation available for teams that already have Redux hardware while warning teams about the company's status.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: 2 people

source/docs/software/can-devices/third-party-devices.rst

@@ -95,7 +95,9 @@ Playing With Fusion (PWF) offers the Venom integrated motor/controller as well a
 
 ## Redux Robotics
 
-Redux Robotics currently offers the HELIUM Canandmag :term:`CAN` + :term:`PWM` magnetic encoder and the BORON Canandgyro :term:`CAN`-enabled gyro.
+.. warning:: Redux Robotics is shutting down. While their devices remain legal for FRC use and software support will be provided for the 2026 season, no new hardware will be available.
+
+Redux Robotics offers the HELIUM Canandmag :term:`CAN` + :term:`PWM` magnetic encoder and the BORON Canandgyro :term:`CAN`-enabled gyro.
 
 ### Redux Sensors