* Add parser.seen for multiple parameters
* Fix M666, use !seen for report
* Synchronize on M204, M205

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

- Followup fixes for menu refactor
- Fix TMC sanity checks, unused var warnings

In response to #12272

Fix LEVEL_BED_CORNERS menu not found

- Add `axis_t`, `extruder_t`, `heater_t`, and `fan_t` to eliminate ambiguity, improve type safety.
- Regularized getter/setter argument order and naming.
- `setAxisPosition` no longer stacks moves in the buffer, allowing it to be called repeatedly on each touch ui tap.
- Implement better manual moves for `EXTENSIBLE_UI` (#12205)
- Calling `setAxisPosition_mm` no longer buffers the entire move to the new position, but instead causes small moves towards it to be made during the idle loop. This allows the user to adjust the destination even after the move has started and makes the UI feel much more responsive.
- As suggested by @ejtagle, the new code keeps the planner buffer full to ensure smooth motion without stops and starts.
- Change `En`, `Hn` and `FANn` to zero-based indices.
- Labels consistent with the rest of Marlin code.