Default Studio expose to software H.264 and smooth streaming

[DjDeveloperr]

Summary

• Switch simdeck studio expose to software H.264 by default and add --hardware-h264 for explicit hardware encode selection.
• Update the smooth stream profile to 1170px at up to 60 fps with higher bitrate, and surface the active codec/profile in the Studio startup output.
• Improve remote stream resilience by tolerating brief WebRTC disconnects, suppressing transient fetch errors, and keeping playback alive during reconnects.
• Refresh the README, CLI docs, and operator guide to match the new Studio defaults and flags.

Testing

• Not run (not requested).