ci: add premerge check for tilegym- skill naming convention

[hannahli-nv]

Summary

• Add .github/scripts/check_skill_naming.py — a lightweight Python script that detects any new skills/<name>/ directory added in a PR and verifies that:
  1. The directory name starts with tilegym-
  2. The name: field in skills/<name>/SKILL.md starts with tilegym-
• Add .github/workflows/check-skill-naming.yml — a GitHub Actions workflow that runs the above script on every PR touching skills/**. The workflow only fires when skills/ changes, so it adds no overhead to unrelated PRs.

Motivation

Skills published to the nvidia/skills registry must use project-scoped prefixes to avoid name collisions. Existing TileGym skills were already renamed to tilegym-*. This check enforces the convention for all future contributions — failing at premerge with a clear message and fix instructions rather than discovering the issue post-merge.

The check is additive: it only inspects newly added skill directories, so it never blocks PRs that modify existing skills.

Error output when a violation is found

========================================================================
SKILL NAMING VIOLATION -- 1 skill(s) must be renamed
========================================================================

Skill: skills/my-new-kernel/
  * Directory name "my-new-kernel" does not start with "tilegym-"
  * `name: "my-new-kernel"` in SKILL.md does not start with "tilegym-"

WHY this rule exists
--------------------
  TileGym skills are published to the nvidia/skills registry, where skills
  from many NVIDIA projects coexist. The "tilegym-" prefix prevents name
  collisions and makes the origin of each skill immediately clear to users.

HOW to fix
----------
  1. Rename the skill directory:
         git mv skills/my-new-kernel  skills/tilegym-my-new-kernel

  2. Update the `name:` field in skills/tilegym-my-new-kernel/SKILL.md:
         name: "tilegym-my-new-kernel"

  3. If other SKILL.md files reference this skill by name,
     update those references too.

Test plan

• Verify workflow triggers on a PR that adds a skills/ directory
• Verify job passes when new skill has tilegym- prefix
• Verify job fails with clear message when new skill lacks the prefix
• Verify job is skipped (not triggered) on PRs that don't touch skills/

CI Configuration

config:
  build: false
  test: []

🤖 Generated with Claude Code

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