On IDEX setup, START_PRINT will always heat T0 to print temperature even if it's not used

[rms497]

What happened

RatOS START_PRINT currently assumes the default Beacon/probing toolhead should always be heated to full first-layer extrusion temperature during print startup, even when that toolhead is not used for printing.

Example:

• T0 = Beacon/default probing toolhead
• T1 = active print toolhead
• Print uses ONLY T1

Current behavior:

• RatOS still heats T0 to the full slicer first-layer temperature (e.g. 330C for PPS-CF)
• RatOS waits for T0 to reach temperature
• Later, RatOS may cool T0 back down if unused

This causes unnecessary:

• filament heat cycling
• nozzle cooking/carbonization
• clog risk
• long startup delays
• thermal stress on the inactive toolhead

This is especially problematic for very high temperature materials where the inactive toolhead may sit at 300C+ for several minutes with no extrusion occurring.

This issue appears to originate from the START_PRINT logic that couples:

• "default Beacon toolhead"
  with
• "active print toolhead"
  during extruder heating.

What did you expect to happen

• If a toolhead is ONLY needed for Beacon/contact probing, heat it only to beacon_contact_true_zero_temp
• Only heat a toolhead to full extrusion temperature if it is actually used in the print
• Leave completely unused toolheads cold

How to reproduce

Slice a part using only T1 as the build tool and send to printer. Both T0 and T1 will heat to first layer temperature after beacon contact true zero calibration, even though only T1 will be used.

Additional information

No response