Expand render pipeline, outputs, lighting, import and pre-flight (1.9.0)

Render pipeline
- Render All runs modally: status bar progress and time left, Esc
  stops after the image in flight, scene state always restored
- Skip Existing resumes a crashed or cancelled batch
- Per-product render ticks and Render Active; labels stay stable
  when products are unticked
- Per-view checkboxes (Custom view set) and per-custom-view toggles
- Reframe Before Rendering rebuilds cameras at render time

Outputs
- Naming templates for files and folders ({label} {prefix}
  {number} {product} {view} {mode}), with clash detection
- Contact sheet per product with captions
- Turntables: frames plus H.264 MP4 and looping GIF
- Post-processed copies: trim, pad to square, flatten, PNG/JPEG/WebP,
  max size and extra sizes; originals untouched
- CSV/JSON manifest, merged across partial runs

Look and lighting
- Lights follow the camera so every view is lit like Front
- Ground: shadow catcher or floor, placed under each product
- HDRI background, optionally hidden from camera
- Line art, mask and AO passes
- Material presets for the batch or per product, applied through a
  temporary Geometry Nodes modifier
- Save and delete your own lighting presets

Import and geometry
- STEP parts import as separate named objects with their CAD
  colours, read from the STEP file since console FreeCAD drops them
- IGES via FreeCAD; OBJ, PLY, glTF/GLB, FBX via Blender; 3MF via a
  small built-in reader
- Add a whole folder, optionally recursive
- Real size and units recorded at import; Keep Proportions scale
  mode; Rest on Floor
- Auto Orient (lay flat or principal axes) and Reset Orientation

Pre-flight
- Checks the batch before rendering, with one-click fixes; errors
  stop Render All, warnings ask first; empty products are skipped

Fixes
- FreeCAD import meshed assembly containers and origin planes,
  duplicating every part of a multi-part STEP
- Stray-object check crashed on stale view layer entries
- Stop setting deprecated use_nodes on Blender 5

Author: Danyals-code