Bump version: 3.1.0 → 3.2.0

[leandropineda]

bump2version minor (no tag — see below). Releases the video capture work merged since 3.1.0:

• Reopen a dropped video stream instead of spinning on a dead capture #105 — a dropped stream is reopened with backoff instead of spinning the capture thread on a dead handle at 100% of a core, so video returns without restarting the connector. URL sources now request cv2.CAP_FFMPEG explicitly, so OPENCV_FFMPEG_CAPTURE_OPTIONS (RTSP transport, socket timeout) actually applies.
• Decode video frames at the publish rate, not the stream rate #109 — the grab loop no longer holds capture_mutex (it was starving get_frame_jpg), and frames are converted to BGR at the publish rate rather than per grab.
• Stop serving a stale video frame as if the stream were live #107 — behaviour change: frames older than the staleness window are no longer served, so a stream that died shows no video instead of a frozen picture that looks live. The window defaults to three publish periods (1s at 10 fps, 3s at 1 fps, 30s at 0.1 fps) with a 1s floor; stale_frame_seconds overrides it and float("inf") restores the old behaviour.
• Log capture health so a video outage points at a layer #108 — a per-minute capture health line (grabbed/served/stale/reopens) plus video_frames_grabbed, video_frames_stale and video_capture_reopens OTEL counters, and the README's first camera-streaming section.

Release notes should call out #107: a consumer that relied on the last frame being re-served forever needs stale_frame_seconds=float("inf").

Tagging: run with --no-tag because past bumps were squash-merged (Bump version: 3.0.0 → 3.1.0 (#104)), which discards the branch commit a local tag would point at. After merge, on updated main:

git tag v3.2.0 && git push --tags

The squashed commit message still contains "Bump version", so the PyPI publish job in build-main.yml fires on merge; the tag only keeps setup.py's download_url resolvable.