Add configurable high-resolution K1 Max bed mesh

[AlexFridman]

Summary

Add an optional, configurable full-bed mesh workflow for K1 Max PRTouch v2 printers:

• BED_LEVELING POINTS=9 produces a 9x9 mesh.
• BED_LEVELING POINTS=10 produces a 10x10 mesh.
• Coordinates remain inside the configured mesh_min / mesh_max; Klipper calculates uniform spacing as (max - min) / (points - 1).
• The configured [bed_mesh] probe_count and stock G29 workflow are not changed.

Why

Creality PRTouch v2 initializes exactly 36 per-point threshold entries and indexes them with the current G29 point number. A grid larger than 6x6 therefore reaches an out-of-range entry at point 37 even though Klipper bed mesh supports larger grids.

The bundled KAMP macro also recalculates its density from the static [bed_mesh] probe_count, so an explicit higher PROBE_COUNT is currently reduced back to the configured density.

Creality source reference: https://github.com/CrealityOfficial/K1_Series_Klipper/blob/main/klippy/extras/prtouch_v2_wrapper.py

A static audit of that backend found no other fixed-size structures indexed by the G29 point counter; the two threshold tables are the only 36-entry limit.

Changes

• Add POINTS=3..10 to the existing BED_LEVELING useful macro while retaining PROBE_COUNT=x,y compatibility.
• Calculate and report the actual X/Y spacing from the active mesh bounds.
• Fail before generated G-code executes when:
  • both POINTS and PROBE_COUNT are supplied;
  • the requested dimensions are outside 3..10;
  • more than 36 total points are requested on a non-PRTouch-v2 backend;
  • the PRTouch extension is missing or too small.
• Add a K1-only Helper Script improvement that extends the PRTouch v2 threshold tables to 100 entries without replacing probing, homing, or motion code.
• Refuse installation unless the printer reports pr_version: 2 (current K1 Max configuration); K1/K1C/K1 SE PRTouch v1 configurations are not patched.
• Detect a pre-existing manual PRTouch extension module or config and stop without changing files, preventing duplicate sections during migration.
• Let KAMP accept an explicit probe count and add an internal FULL_BED=1 path that bypasses adaptive object bounds, margin, and fuzzing only for this calibration.
• Add install/remove/info menu integration, dependency checks, documentation, and unit tests.

Safety properties

• Stock G29 and the static [bed_mesh] probe_count remain unchanged.
• The feature uses the configured mesh bounds, not physical bed limits.
• Requests above 10x10 are rejected.
• Unsupported PRTouch backends fail closed.
• Existing manual extension installs are never overwritten automatically.
• New threshold entries are independent copies of the final configured threshold pair; the official K1 Max configurations use identical pairs for all 36 factory entries.
• No mesh is saved automatically.

Validation

• python3 -m unittest discover -s tests -v — 10 tests pass with Jinja2 installed (the 4 PRTouch module tests remain stdlib-only).
• Python module compilation passes.
• All modified shell files pass syntax checks.
• A temporary-filesystem installer test passes manual-config conflict detection, manual-module conflict detection, install, repeated install (no duplicate include), and remove.
• Klipper/Jinja render checks pass for 6x6, 9x9, and 10x10.
• K1 Max default 5..295 mm bounds render spacings of 58.00, 36.25, and 32.22 mm respectively.
• KAMP renders full-bed native calls for 6x6, 9x9, and 10x10 without adapting the bounds.
• Missing-extension and PRTouch-v1 paths reject 9x9 before executing generated G-code.
• Official current K1 family configs were checked: K1 Max uses PRTouch v2; K1/K1C/K1 SE use PRTouch v1.
• An equivalent 100-entry extension has completed an 81/81-point 9x9 mesh on a K1 Max, board CR4CU220812S12, firmware 1.3.5.22.

Hardware follow-up before marking ready

• Install this exact branch through the Helper Script on the test K1 Max.
• Re-run 9x9 as a regression test.
• Run and inspect a full 10x10 / 100-point mesh.
• Verify uninstall restores the normal 6x6 workflow.