fix: H2C carousel - port BBS NozzleStatusRecorder for per-slot purge tracking (#14800)

## Problem

On H2C (carousel) printers, the wipe tower purge volume calculation in
`_make_wipe_tower()` tracks filament state **per-extruder** (2 slots).
Since H2C has up to 7 carousel nozzle slots on a single extruder, all
filaments sharing that extruder are collapsed into one tracking slot.
This causes:

Test:

[5cubes.3mf.zip](https://github.com/user-attachments/files/30092551/5cubes.3mf.zip)

- **Massive redundant AMS flushing** every filament change on the
carousel triggers a full purge against the "previous" filament, even
when the target nozzle slot already has the correct filament loaded
- **60.9g total weight** instead of ~17g (**3.5× material waste**)
- **3h09m print time** instead of ~1h57m (**60% longer**)

## Root Cause

The code uses `nozzle_cur_filament_ids[extruder_id]` (a 2-element array)
to track which filament was last used for each extruder. BambuStudio
uses `NozzleStatusRecorder`, which tracks per `group_id` (physical
carousel slot 0..6).

## Changes

| File | Change |
|---|---|
| `Print.cpp` | Replace `nozzle_cur_filament_ids` with
`NozzleStatusRecorder`. Use `get_nozzle_for_filament()` to resolve the
physical carousel slot per layer. Select `filament_prime_volume_nc` for
nozzle changes, `filament_prime_volume` for filament changes. |
| `PrintConfig.hpp` | Add `ConfigOptionFloats filament_prime_volume`
(per-filament EC prime volume, missing from upstream but present in BBS
and H2C profiles) |
| `PrintConfig.cpp` | Register `filament_prime_volume` with default
45mm³ (matching BBS) |
| `Preset.cpp` | Add `filament_prime_volume` to preset keys |

Also includes `tests/compare_analyzer/` - two standalone Python tools
for G-code slice comparison and temperature timeline analysis (stdlib
only, no dependencies).

## Test Results (5-color H2C Hybrid print, same 3mf project)

| Metric | Upstream (broken) | **Fixed** | BBS (reference) |
|---|---|---|---|
| **Total weight** | 60.90g | **16.20g** ✅ | 17.47g |
| **Print time** | 3h09m | **1h57m** ✅ | 1h51m |
| **Filament changes** | 105 | 105 | 140 |
| **Tool changes** | 35 | 35 | 35 |
| **Critical discrepancies vs BBS** | ⚠️ YES | ✅ None | — |


## Analysis Tools (`tests/compare_analyzer/`)

Two standalone Python tools (stdlib only, no dependencies) for deep
G-code comparison:

- **`compare_slices.py`** - comprehensive .3mf slice comparison:
filament usage, nozzle mapping, tool change sequences, prime tower
analysis, temperature timeline, retract parameters, and automatic
critical discrepancy detection (weight/time anomalies)
- **`show_temp_plot.py`** - interactive HTML temperature timeline
plotter for visualising heater profiles during multi-nozzle prints
(supports single-file and side-by-side comparison)

Usage:
```bash
python3 tests/compare_analyzer/compare_slices.py file1.3mf file2.3mf --labels "Upstream" "Fixed"
python3 tests/compare_analyzer/show_temp_plot.py file1.3mf file2.3mf
```


## Screenshots

### OrcaSlicer Upstream (unfixed) - 60.90g, 3h09m
<img width="1512" height="982" alt="Screenshot 2026-07-16 at 15 22 58"
src="https://github.com/user-attachments/assets/3efb2bff-ff1e-43db-9669-feafa5921b51"
/>


### OrcaSlicer Fixed - 16.20g, 1h57m
<img width="1512" height="982" alt="Screenshot 2026-07-16 at 15 23 08"
src="https://github.com/user-attachments/assets/c1d36dc5-9b01-4691-80ef-7364540e1f4e"
/>

### BambuStudio Reference - 17.47g, 1h51m
<img width="1512" height="982" alt="Screenshot 2026-07-16 at 15 24 52"
src="https://github.com/user-attachments/assets/5c0b11e2-64f4-40e9-8c7c-3f42519786c3"
/>

### Temperature Timeline: Upstream vs Fixed
<img width="1511" height="829" alt="Screenshot 2026-07-16 at 15 23 35"
src="https://github.com/user-attachments/assets/926c2cb5-dfd4-4ce0-bb40-82e6165eb134"
/>


### Temperature Timeline: Fixed vs BBS

<img width="1512" height="825" alt="Screenshot 2026-07-16 at 15 23 51"
src="https://github.com/user-attachments/assets/85c72dda-e779-4aa6-8118-fb17e5f8482d"
/>


## Compatibility

Safe for non-carousel printers: when each extruder has a single nozzle,
`group_id == extruder_id`, so `NozzleStatusRecorder` behaves identically
to the original per-extruder tracking. The `filament_prime_volume`
default (45mm³) matches the existing global `prime_volume` default.

## Reference
BambuStudio `Print.cpp` `_make_wipe_tower()` L3341-3392 -
`NozzleStatusRecorder` pattern.

tests/compare_analyzer/README.md

@@ -0,0 +1,88 @@
+# Compare Analyzer — G-code Slicing Comparison Tools
+
+Tools for deep comparison and analysis of `.3mf` slicing project files, designed for
+verifying multi-nozzle (H2C carousel) and multi-extruder slicing correctness.
+
+## Tools
+
+### `compare_slices.py` — Slice Comparison Analyzer
+
+Deep comparison of two `.3mf` files (OrcaSlicer, BambuStudio, or any compatible slicer).
+Generates a comprehensive Markdown report covering:
+
+- **Filament usage** — per-filament weight/length with color mapping
+- **Nozzle/extruder mapping** — Vortek carousel slot assignments
+- **Tool change sequences** — T-code ordering and count
+- **Prime tower analysis** — tower entries, G-code line count
+- **Temperature timeline** — pre-heat lead times, target temperatures per tool change
+- **Retract parameters** — M620.11 analysis during nozzle switches
+- **Filament change G-code blocks** — line-by-line diff of change_filament_gcode
+- **Control command diff** — timeline of M/G-code differences
+- **Critical discrepancy detection** — automatic flagging of weight/time anomalies
+
+#### Usage
+
+```bash
+# Compare two slice files
+python3 compare_slices.py file1.3mf file2.3mf
+
+# With custom labels
+python3 compare_slices.py file1.3mf file2.3mf --labels "Upstream" "Fixed"
+```
+
+#### Output
+Markdown report saved to `mp_reports/compare_report_YYYYMMDD_HHMMSS.md`
+
+#### Example: Detecting H2C purge regression
+```
+⚠️ CRITICAL DISCREPANCY: Huge difference in part weight:
+  OrcaSlicer 60.90 g vs BambuStudio 17.47 g (difference 43.43 g or 71.3%).
+  The reason is incorrect nozzle mapping, causing huge AMS flushing.
+```
+
+---
+
+### `show_temp_plot.py` — Temperature Timeline Plotter
+
+Generates interactive HTML temperature plots for analyzing thermal profiles during
+multi-nozzle prints. Visualizes heater temperature commands (M104/M109) per tool change,
+showing pre-heat timing and temperature convergence.
+
+#### Architecture
+- H2C dual-extruder layout with Vortek carousel nozzles
+- Physical heaters mapped dynamically:
+  - Heater 0: Extruder 2 (right nozzle slot, T0/T2/T3/T4)
+  - Heater 1: Extruder 1 (left nozzle slot, T1)
+- Active heater mapping derived from G-code temperature signals
+
+#### Usage
+
+```bash
+# Single file analysis
+python3 show_temp_plot.py file.3mf
+
+# Side-by-side comparison of two files
+python3 show_temp_plot.py file1.3mf file2.3mf
+```
+
+#### Output
+Interactive HTML report saved to Desktop as `temp_plot_v3.html`
+
+---
+
+## Requirements
+
+- **Python 3.8+**
+- **No external dependencies** — uses only Python standard library
+  (`json`, `zipfile`, `xml.etree.ElementTree`, `difflib`, `webbrowser`)
+
+## Use Cases
+
+1. **Regression testing** — compare slices before/after code changes to verify
+   no unintended differences in purge volumes, tool ordering, or temperature timing
+2. **BBS compatibility verification** — compare OrcaSlicer output against BambuStudio
+   reference slices to ensure behavioral parity
+3. **H2C carousel validation** — verify per-slot nozzle tracking produces correct
+   purge volumes (not collapsed per-extruder)
+4. **Temperature protocol analysis** — verify pre-heat lead times and cooling
+   temperatures during nozzle changes match expected profiles