- Drop `pgm_read_*_near` and let headers choose.
- Define `USE_EXECUTE_COMMANDS_IMMEDIATE` as a conditional.
- Add `process_subcommands_now` for SRAM-based commands.

- Move FWRETRACT to the planner
- Combine leveling, skew, etc. in a single modifier method
- Have kinematic and non-kinematic moves call one planner method

When possible, make `active_extruder` a `constexpr` to save some PROGMEM.

On many IDEX machines the allowed travel of the X1 carraige and X2 carraige does not perfectly overlap.

This helps the issue.   But more work needs to be done at the higher level.  (For example the X1_MAX_POS should probably be factored into G26's mesh validation pattern.)

Use macros that explicitly avoid double-evaluation and can be used for any datatype, replacing `min`, `max`, `abs`, `fabs`, `labs`, and `FABS`.

Co-Authored-By: ejtagle <ejtagle@hotmail.com>

Some probes don't work near the edges of the bed. This change promotes MIN_PROBE_EDGE to a general setting that applies to all probing functions.

Fix #10029

Fix #10029

Previously `position_is_reachable_by_probe` was limited to the area specified for `G29` mesh leveling (even if leveling was disabled). This change will properly consider the entire bed area so that `G30` and other non-leveling probing may take place.

Fix #9732

set_destination_to_current() changed to set_destination_from_current()

set_current_to_destination() changed to set_current_from_destination()