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>

src/skill_seekers/cli/create_command.py

@@ -398,6 +398,12 @@ class CreateCommand:
         vs = getattr(self.args, "visual_similarity", None)
         if vs is not None and vs != 3.0:
             argv.extend(["--visual-similarity", str(vs)])
+        st = getattr(self.args, "start_time", None)
+        if st is not None:
+            argv.extend(["--start-time", str(st)])
+        et = getattr(self.args, "end_time", None)
+        if et is not None:
+            argv.extend(["--end-time", str(et)])
 
         # Call video_scraper with modified argv
         logger.debug(f"Calling video_scraper with argv: {argv}")