### Pupil Segmentation Integration

- **Objective:** Integrated Pupil segmentation into the mono camera pipelines.
- **Key Changes:**
    - Modified `src/unified_web_ui/gstreamer_pipeline.py` to:
        - Add a `tee` element for mono camera streams to split the video feed.
        - Create a new branch for pupil segmentation with a `videoconvert` placeholder and a dedicated `appsink` (`seg_sink_{i}`).
        - Implement `on_new_seg_sample_factory` callback to handle segmentation data.
        - Added `seg_frame_buffers` and `seg_buffer_locks` for segmentation output.
        - Introduced `get_seg_frame_by_id` to retrieve segmentation frames.
        - Ensured unique naming for `tee` elements (`t_{i}`) in the GStreamer pipeline to prevent linking errors.
    - Modified `src/unified_web_ui/app.py` to:
        - Add a new Flask route `/segmentation_feed/<int:stream_id>` to serve the segmentation video stream.
        - Added `datetime.utcnow` to the Jinja2 context for cache-busting in templates.
    - Modified `src/unified_web_web_ui/templates/index.html` to:
        - Include a new "Segmentation Feed" section displaying the segmentation video streams, sourcing from `/segmentation_feed/` with cache-busting timestamps.
        - Updated existing video feeds (`video_feed`) with cache-busting timestamps for consistency.
- **Testing:**
    - Created `tests/test_segmentation.py` to verify the segmentation feed is visible and updating.
    - Updated `src/unified_web_ui/tests/test_ui.py` to refine locators (`#camera .camera-streams-grid .camera-container-individual`) for camera stream elements, resolving conflicts with segmentation feeds.
    - Updated `src/unified_web_ui/tests/test_visual.py` to refine locators (`#camera .camera-mono-row`, `#camera .camera-color-row`, `#camera .camera-mono`) to prevent strict mode violations and ensure accurate targeting of camera layout elements.
    - Fixed indentation errors in `src/unified_web_ui/tests/test_visual.py`.
- **Status:** All tests are passing, and the infrastructure for pupil segmentation is in place, awaiting the integration of a DeepStream model.