feat(#267): expose TUTK/Kalay camera credentials as Granary camera feeder attributes

[dennismdejong]

Summary

Closes #267 — expose the Granary Smart Camera Feeder's TUTK/Kalay camera credentials as sensor attributes so users can use them with external TUTK clients (e.g. go2rtc) to stream the feed locally.

The issue author verified that POST /member/third/tutk/info (empty payload) works for both primary and shared accounts, returning data.userToken + data.appTutkUrl. The cameraId (20-char Kalay UID) comes from the device record, and cameraAuthInfo from realInfo.

Changes

• api.py: new tutk_info() method for /member/third/tutk/info (account-scoped, empty payload)
• granary_smart_camera_feeder.py:
  • refresh fetches TUTK info (isolated in its own try/except so a failure can't break the whole refresh)
  • new properties: camera_id, camera_auth_info, tutk_user_token, tutk_app_url, enable_camera, camera_switch, motion_detection_switch, sound_detection_switch
• sensor.py: exposes these as attributes on the wifi_ssid sensor entity of the device (single entity, not duplicated across all sensors)
• README.md: note documenting the exposed credentials

Scope

This deliberately does not build a full camera platform (would require bundling the IOTC SDK / go2rtc bridge). It provides the credential layer every streaming approach needs. IOTC/streaming README depth left to the maintainer's judgment.

Review feedback applied

• Fixed TypeError from merging extra_state_attributes when HA returns None
• Isolated tutk_info in refresh so a failed call degrades gracefully
• Scoped attributes to a single entity (wifi_ssid) to avoid duplicating credentials across ~15 sensors
• Removed unused serial parameter (endpoint is account-scoped)

[dennismdejong]

@jjjonesjr33 @Sarcaris2000 PR is open for the TUTK/Kalay camera credential exposure discussed in #267. Scope is deliberately minimal (credential attributes + docs, no full camera platform). @Sarcaris2000 — thanks again for confirming the endpoint shapes; if you want to verify the attributes against your shared-account setup once merged, that would be great.