feat: extend VISUAL_C07 support with controls and event images

[129tyc]

Summary

Adds support for the CATLINK DaBai Pro (大白 Pro) camera-enabled
self-cleaning litter box, identified by the CATLINK API as VISUAL_C07.

The implementation was exercised against a real CATLINK DaBai Pro device for
device discovery, state retrieval, event data, and event images.

Not every control action was individually verified against the physical device;
additional hardware validation may be needed for the full control surface.

Supported sensors

• Device state, online status, error status
• Cleaning status and event state
• Automatic, manual, clear, full-bin, and total cleaning counts
• Cat-litter balance and sandbox balance
• Remaining litter days
• Deodorant countdown
• Garbage-bin status

Supported controls

• Clean, pause, cancel
• Pave, pause, cancel
• Empty, pause, cancel
• Add sand, pause, cancel
• Automatic cleaning
• Kitten mode
• Key lock
• Quiet mode
• Continuous cleaning
• Soft/deep-clean mode
• Voice prompt, panel tone, watermark
• Camera selection
• Box-full sensitivity
• Pave level, litter type, safe cleaning time, fill-light mode
• Add-sand copies

Event images

• Last event before
• Last event after
• Last event on site

Limitations

• Support is limited to VISUAL_C07.
• Live video and two-way audio are not included.
• Temperature, humidity, litter weight, empty status, work mode, and event
  thumbnail are not exposed as standalone entities because they are not
  reliably available or displayed for this model.

[129tyc]

I noticed PR #65 after opening this PR. The two PRs overlap on the
VISUAL_C07 / DaBai Pro baseline, but are not functionally identical.

This PR additionally provides C07 write controls/actions, camera switch control,
and separate before-event, after-event, and on-site event images.

I suggest coordinating the final implementation with PR #65 rather than
stacking both implementations mechanically. I am happy to use the
maintainers' preferred baseline and port the additional capabilities if needed.

[129tyc]

Added a companion project for CATLINK Visual C07 video support. It provides cloud/local RTSP streams and can be used alongside this integration:
https://github.com/129tyc/catlink-stream-bridge