Add sssf skill, installable via the skills CLI

Port the sssf skill from ~/.agents/skills/sssf into this repo so it can be
distributed and installed with the skills CLI (skills add INDigitalStudio/skills
--skill sssf).

- Copy the skill (SKILL.md, cookbooks, references, scripts, templates, and the
  visualizer app source) into sssf/.
- Gitignore build/runtime artifacts: the visualizer's node_modules/ and dist/,
  Python bytecode, and the machine-specific repos.json.
- Make the skill location-independent: install.py now stamps the skill's real
  path into the stamped justfile's skill_dir (replacing the hardcoded
  ~/.agents/skills/sssf), so 'just obs' finds the visualizer wherever the CLI
  installed the skill.
- Update cookbooks to use <skill>/scripts/... instead of the hardcoded path,
  and document the skills CLI install command.
- Update the repo README with install instructions.

sssf/scripts/make_config.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env -S uv run
+# /// script
+# dependencies = []
+# ///
+"""make_config — generate adws/adw_sssf_config/sssf.config.yaml with great defaults.
+
+Usage:
+    uv run <skill>/scripts/make_config.py [--force]
+"""
+
+import argparse
+import shutil
+import sys
+from pathlib import Path
+
+TEMPLATE = Path(__file__).resolve().parent.parent / "templates" / "sssf.config.yaml"
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--force", action="store_true")
+    args = parser.parse_args()
+
+    dest = Path.cwd() / "adws" / "adw_sssf_config" / "sssf.config.yaml"
+    if dest.exists() and not args.force:
+        print(f"{dest} already exists — use --force to overwrite")
+        return 1
+    dest.parent.mkdir(parents=True, exist_ok=True)
+    shutil.copy2(TEMPLATE, dest)
+    print(f"wrote {dest}")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())