The high-level Remotion render path hid the useful failure reason. run_command
runs with check=True + capture_output, so a non-zero exit raised
CalledProcessError whose str() is only 'returned non-zero exit status 1' — the
actual Remotion diagnostics in stderr were dropped. Catch CalledProcessError
and surface the stderr/stdout tail, and TimeoutExpired with an actionable hint.
Also add a creator-facing remotion_timeout_ms input, passed through as
Remotion's --timeout (headless-browser setup + delayRender). Slow browser
startup on restricted networks previously failed opaquely at the default 30s
with no way to raise it. The subprocess timeout is widened to match so
run_command does not kill Remotion before its own timeout fires.
Closes#217
fbbe32a676