apply_nous_managed_defaults() was adding image_gen and video_gen to the
'changed' return set without writing any config values. The caller
(tools_command first_install flow) uses 'changed' to skip manual
configuration, so these tools ended up in platform_toolsets but with no
video_gen.provider, video_gen.use_gateway, or image_gen.use_gateway in
config.yaml.
At runtime the FAL plugin's is_available() returned False because there
was no FAL_KEY and no use_gateway config — the tool never loaded despite
being 'enabled' in the toolset list.
For image_gen this was a latent bug masked by the gateway offer prompt
(prompt_enable_tool_gateway) running earlier in the setup flow and
writing image_gen.use_gateway=True via apply_gateway_defaults(). But if
the user skipped the gateway offer, image_gen would silently break the
same way.
For video_gen (added in PR #33259) the bug was always hit because the
gateway offer ran before the user checked video_gen in the toolset
checklist.
Fix: write provider/use_gateway config values before adding to 'changed',
matching the pattern used by web, tts, and browser.
aa32edcac5