Add Segmentation Editing tab with 5-row layout

- Row 1: Magic Code textbox + Submit button
- Row 2: Segment ID dropdown (hidden initially)
- Row 3: ImageEditor component for SAM-3 style interaction (hidden initially)
- Row 4: Frame number slider (hidden initially)
- Row 5: Download Segment button (hidden initially)

Rows 2-5 become visible after magic code submission.
All functions are placeholders ready for backend integration.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app.py

@@ -90,6 +90,62 @@ def process_video(video_path, notes, email, company_name) -> str:
         logger.error(f"Unexpected error in process_video: {e}")
         return "Unexpected error during video processing."
 
+
+# Placeholder functions for Segmentation Editing tab (future backend integration)
+def submit_magic_code(magic_code):
+    """
+    Placeholder function to validate magic code and retrieve segment list.
+    TODO: Connect to backend API endpoint for magic code validation.
+    """
+    if not magic_code:
+        return (
+            gr.update(choices=[]),  # dropdown
+            "Please enter a magic code",  # status message
+            gr.update(visible=False),  # row2
+            gr.update(visible=False),  # row3
+            gr.update(visible=False),  # row4
+            gr.update(visible=False)   # row5
+        )
+
+    # Placeholder: Simulate retrieving segment IDs
+    logger.info(f"Magic code submitted: {magic_code}")
+    sample_segments = ["Segment_001", "Segment_002", "Segment_003"]
+
+    return (
+        gr.update(choices=sample_segments, value=sample_segments[0]),  # dropdown
+        f"Loaded {len(sample_segments)} segments",  # status message
+        gr.update(visible=True),   # row2
+        gr.update(visible=True),   # row3
+        gr.update(visible=True),   # row4
+        gr.update(visible=True)    # row5
+    )
+
+
+def load_segment_frame(segment_id, frame_number):
+    """
+    Placeholder function to load a specific frame from a segment for editing.
+    TODO: Connect to backend API to retrieve frame image from video segment.
+    """
+    if not segment_id:
+        return None
+
+    logger.info(f"Loading segment: {segment_id}, frame: {frame_number}")
+    # Placeholder: Return None (no image loaded yet)
+    return None
+
+
+def download_segment(segment_id, edited_image, frame_number):
+    """
+    Placeholder function to download edited segment.
+    TODO: Connect to backend API to save edited segmentation and download result.
+    """
+    if not segment_id:
+        return "No segment selected"
+
+    logger.info(f"Download requested for segment: {segment_id}")
+    return f"Download functionality coming soon for {segment_id}"
+
+
 # Create a professional Gradio interface using the Golden ratio (1.618) for proportions
 # Define custom CSS for a professional look
 css = """
@@ -319,7 +375,51 @@ with gr.Blocks(css=css, theme=gr.themes.Soft(primary_hue="indigo", secondary_hue
             
             with gr.Tab("Segmentation Editing"):
                 gr.Markdown("### Segmentation Editing Workspace")
-                gr.Markdown("This feature is currently under development.")
+
+                # Row 1: Magic Code textbox + Submit button
+                with gr.Row(elem_classes="input-section"):
+                    with gr.Column(scale=3):
+                        seg_magic_code = gr.Textbox(
+                            label="Magic Code",
+                            placeholder="Enter your magic code...",
+                            interactive=True
+                        )
+                    with gr.Column(scale=1):
+                        seg_submit_btn = gr.Button("Submit Code", variant="primary")
+
+                # Row 2: Segment ID dropdown
+                with gr.Row(elem_classes="input-section", visible=False) as seg_row2:
+                    seg_id_dropdown = gr.Dropdown(
+                        label="Segment ID",
+                        choices=[],
+                        interactive=True,
+                        info="Select a segment to edit"
+                    )
+
+                # Row 3: ImageEditor component (SAM-3 style interaction)
+                with gr.Row(elem_classes="input-section", visible=False) as seg_row3:
+                    seg_image_editor = gr.ImageEditor(
+                        label="Image Click Segmentation",
+                        type="pil",
+                        interactive=True,
+                        brush=gr.Brush(colors=["#FF0000"], color_mode="fixed")
+                    )
+
+                # Row 4: Frame number slider
+                with gr.Row(elem_classes="input-section", visible=False) as seg_row4:
+                    seg_frame_slider = gr.Slider(
+                        minimum=0,
+                        maximum=100,
+                        value=0,
+                        step=1,
+                        label="Frame Number",
+                        interactive=True,
+                        info="Select video frame to segment"
+                    )
+
+                # Row 5: Download Segment button
+                with gr.Row(visible=False) as seg_row5:
+                    seg_download_btn = gr.Button("Download Segment", variant="secondary")
 
     # Wire Content Moderation processing
     cm_process_btn.click(
@@ -328,6 +428,31 @@ with gr.Blocks(css=css, theme=gr.themes.Soft(primary_hue="indigo", secondary_hue
         outputs=cm_video_out
     )
 
+    # Wire Segmentation Editing callbacks
+    seg_submit_btn.click(
+        fn=submit_magic_code,
+        inputs=[seg_magic_code],
+        outputs=[seg_id_dropdown, seg_magic_code, seg_row2, seg_row3, seg_row4, seg_row5]
+    )
+
+    seg_id_dropdown.change(
+        fn=load_segment_frame,
+        inputs=[seg_id_dropdown, seg_frame_slider],
+        outputs=[seg_image_editor]
+    )
+
+    seg_frame_slider.change(
+        fn=load_segment_frame,
+        inputs=[seg_id_dropdown, seg_frame_slider],
+        outputs=[seg_image_editor]
+    )
+
+    seg_download_btn.click(
+        fn=download_segment,
+        inputs=[seg_id_dropdown, seg_image_editor, seg_frame_slider],
+        outputs=[seg_magic_code]  # Display status message in magic code textbox
+    )
+
 if __name__ == "__main__":
     # To run this file locally, you'll need to install gradio and requests:
     # pip install gradio requests