Add Anycubic Kobra Neo 0.4 nozzle printer profiles (#12913)

## Summary

Adds proper system profiles for the **Anycubic Kobra Neo** with 0.4mm nozzle (stock Marlin firmware).

This replaces the profiles from #12341 which had several issues:
- All files had `"from": "User"` instead of `"from": "system"` — causing profile loading failures
- No `inherits` or `type` fields — broke the inheritance chain
- Klipper-only gcode (not stock firmware)
- No `Anycubic.json` index entries — printer never appeared in the UI
- Cover image was 382x600 instead of 240x240 (displayed squashed)
- Profiles were subsequently removed in #12889

### Files added/modified

| File | Description |
|------|-------------|
| `machine/Anycubic Kobra Neo.json` | Base machine model (220x220x250mm) |
| `machine/Anycubic Kobra Neo 0.4 nozzle.json` | 0.4mm nozzle variant, stock Marlin gcode |
| `process/0.12mm Detail @Anycubic Kobra Neo 0.4 nozzle.json` | Detail process profile |
| `process/0.16mm Standard @Anycubic Kobra Neo 0.4 nozzle.json` | Standard process profile |
| `process/0.20mm Standard @Anycubic Kobra Neo 0.4 nozzle.json` | Standard process profile |
| `process/0.28mm Standard @Anycubic Kobra Neo 0.4 nozzle.json` | Standard process profile |
| `filament/Anycubic PLA @Anycubic Kobra Neo 0.4 nozzle.json` | PLA filament profile |
| `Anycubic Kobra Neo_cover.png` | Resized to 240x240 |
| `Anycubic.json` | Added index entries for all new profiles |

### Approach

- Based on the working **Anycubic Kobra 2 Neo** profiles (similar hardware — direct drive, 220x220 bed)
- Start gcode uses `G29` for auto bed leveling (stock Kobra Neo probes fresh each print)
- Profiles use proper `"from": "system"` and `"inherits": "fdm_machine_common"` / `"fdm_process_common"` chains
- Buildplate model and texture from #12341 are already in the repo

### Testing

- Verified profiles load correctly in OrcaSlicer 2.3.2 (no errors in log)
- Printer appears in Printer Selection dialog with correct 240x240 cover image
- Process/filament presets appear when printer is selected
- **Note:** Start/end gcode adapted from Kobra 2 Neo for stock Marlin — testing on stock firmware by Kobra Neo owners would be appreciated

Closes the gap left by #12341 and #12889.

resources/profiles/Anycubic/machine/Anycubic Kobra Neo.json

@@ -0,0 +1,12 @@
+{
+    "type": "machine_model",
+    "name": "Anycubic Kobra Neo",
+    "machine_tech": "FFF",
+    "family": "Anycubic",
+    "model_id": "Anycubic Kobra Neo",
+    "nozzle_diameter": "0.4",
+    "bed_model": "Anycubic Kobra Neo_buildplate_model.stl",
+    "bed_texture": "Anycubic Kobra Neo_buildplate_texture.png",
+    "hotend_model": "",
+    "default_materials": "Anycubic Generic PLA"
+}