Arm backend: Add RIFE PTQ/QAT accuracy flow (#20974)

Add a Practical-RIFE PTQ/QAT comparison script under the Arm QAT example
area.

The flow loads original RIFE weights, uses real frame triples, preserves
uint8 image IO by default, and writes JSON, CSV, Markdown, and
quantisation coverage reports.

If a requested triples list is missing, create deterministic random data
for smoke testing. The reports clearly label this as smoke-test data,
not real accuracy data.


cc @digantdesai @freddan80 @per @zingo @oscarandersson8218 @mansnils
@Sebastian-Larsson @robell @rascani

Author: bdemirb