feat: add skill-seekers video --setup for GPU auto-detection and dependency installation

Auto-detects NVIDIA (CUDA), AMD (ROCm), or CPU-only GPU and installs the
correct PyTorch variant + easyocr + all visual extraction dependencies.
Removes easyocr from video-full pip extras to avoid pulling ~2GB of wrong
CUDA packages on non-NVIDIA systems.

New files:
- video_setup.py (835 lines): GPU detection, PyTorch install, ROCm config,
  venv checks, system dep validation, module selection, verification
- test_video_setup.py (60 tests): Full coverage of detection, install, verify

Updated docs: CHANGELOG, AGENTS.md, CLAUDE.md, README.md, CLI_REFERENCE,
FAQ, TROUBLESHOOTING, installation guide, video dependency plan

All 2523 tests passing (15 skipped).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/TROUBLESHOOTING.md

@@ -90,6 +90,35 @@ pyenv install 3.12
 pyenv global 3.12
 ```
 
+### Issue: Video Visual Dependencies Missing
+
+**Symptoms:**
+```
+Missing video dependencies: easyocr
+RuntimeError: Required video visual dependencies not installed
+```
+
+**Solutions:**
+
+```bash
+# Run the GPU-aware setup command
+skill-seekers video --setup
+
+# This auto-detects your GPU and installs:
+# - PyTorch (correct CUDA/ROCm/CPU variant)
+# - easyocr, opencv, pytesseract, scenedetect, faster-whisper
+# - yt-dlp, youtube-transcript-api
+
+# Verify installation
+python -c "import torch; print(f'PyTorch: {torch.__version__}, CUDA: {torch.cuda.is_available()}')"
+python -c "import easyocr; print('easyocr OK')"
+```
+
+**Common issues:**
+- Running outside a virtual environment → `--setup` will warn you; create a venv first
+- Missing system packages → Install `tesseract-ocr` and `ffmpeg` for your OS
+- AMD GPU without ROCm → Install ROCm first, then re-run `--setup`
+
 ## Configuration Issues
 
 ### Issue: API Keys Not Recognized