Fix vision pipeline: ffmpeg removal by autoremove, increase vision timeout, reduce frame count, add Discord activity awareness

- bot/Dockerfile: Add ffmpeg to reinstall line after apt-get autoremove
  (autoremove was sweeping up ffmpeg as 'no longer needed' after playwright install)
- bot/utils/image_handling.py: Increase video analysis timeout 120s→300s, 6→3 for Tenor GIFs (GTX 1660 VRAM constraint)
- bot/utils/activities.py: Add _activity_changed_at timestamp tracking,
  get_current_activity_label() and get_current_activity_fresh() with 30-min decay
- bot/utils/cat_client.py: Pass current Discord activity to Cheshire Cat pipeline
- bot/utils/llm.py: Inject current Discord activity into system prompt
- cat-plugins/*: Forward Discord activity through working_memory to personality plugins
- bot/persona/*/preamble.txt: Add Discord status usage guidelines for character prompts
- llama-swap-rocm-config.yaml: Add qwen3.5 model entry for ComfyUI prompt generation
- AGENTS.md: New project documentation file

bot/utils/image_handling.py

@@ -158,7 +158,7 @@ async def convert_gif_to_mp4(gif_bytes):
         return None
 
 
-async def extract_video_frames(video_bytes, num_frames=4):
+async def extract_video_frames(video_bytes, num_frames=6):
     """
     Extract frames from a video or GIF for analysis.
     Returns a list of base64-encoded frames.
@@ -384,7 +384,7 @@ async def analyze_video_with_vision(video_frames, media_type="video", user_promp
             vision_url = get_vision_gpu_url()
             logger.info(f"Sending video analysis request to {vision_url} using model: {globals.VISION_MODEL} (media_type: {media_type}, frames: {len(video_frames)})")
             
-            async with session.post(f"{vision_url}/v1/chat/completions", json=payload, headers=headers, timeout=aiohttp.ClientTimeout(total=120)) as response:
+            async with session.post(f"{vision_url}/v1/chat/completions", json=payload, headers=headers, timeout=aiohttp.ClientTimeout(total=300)) as response:
                 if response.status == 200:
                     data = await response.json()
                     result = data.get("choices", [{}])[0].get("message", {}).get("content", "No description.")