Feature request: Title: Add configurable movie creation step for V-Ray Standalone tile rendering

[ZainAallii]

Describe the problem

The current movie creation step in create_movie.py uses hardcoded ffmpeg settings
(libx264, yuv420p, crf 18). Different studios have different requirements for codec,
quality, and frame rate. The feature is also marked as "future release" in the codebase
and needs proper validation before shipping.

Proposed Solution

• Expose codec (H.264, H.265), quality (CRF), and output format as job parameters in the UI
• Add validation to check ffmpeg is available on the farm worker before the step runs
• Add unit tests for the movie creation script

Example Use Cases

1. Studio wants lower CRF (higher quality) for client review vs internal dailies
2. Studio needs H.265 for smaller file sizes on high resolution renders
3. Farm workers don't have ffmpeg installed — job should fail with a clear error
   message rather than silently skipping

Related

• PR feat: add V-Ray export workflow with tile rendering #217 (V-Ray Standalone workflow) — movie creation step is currently a stub feat: add V-Ray export workflow with tile rendering #217 (comment)

[ZainAallii]

Created internal ticket.