[Docs] Serve skill.md as both uppercase and lowercase at root

Copy the skill file as both skill.md and SKILL.md at the site root
to support both URL variants.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: peterschmidt85

scripts/docs/hooks.py

@@ -185,8 +185,9 @@ def _write_well_known_skills(config, site_dir):
     out_dir = os.path.join(site_dir, WELL_KNOWN_SKILLS_DIR, name)
     os.makedirs(out_dir, exist_ok=True)
     shutil.copy2(skill_src, os.path.join(out_dir, "SKILL.md"))
-    # Serve skill at site root (e.g. https://dstack.ai/skill.md) from skills/dstack/SKILL.md
+    # Serve skill at site root (both skill.md and SKILL.md) from skills/dstack/SKILL.md
     shutil.copy2(skill_src, os.path.join(site_dir, "skill.md"))
+    shutil.copy2(skill_src, os.path.join(site_dir, "SKILL.md"))
 
     index_path = os.path.join(site_dir, WELL_KNOWN_SKILLS_DIR, "index.json")
     index = {