fix(validate-skills): skip tests/fixtures when discovering skills

The skill validator walks all of src/ recursively, so the bmad-module skill's
reference and negative example modules under tests/fixtures/ (intentionally
non-bmad-* names and deliberately-malformed fixtures) were validated as
production skills and tripped HIGH SKILL-04 name-format findings, failing
`validate:skills --strict`.

Exclude a `fixtures/` directory whose parent is `tests/` from discovery so the
validator judges only real skills. No production skill lives under tests/fixtures/.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/validate-skills.js

@@ -195,6 +195,10 @@ function discoverSkillDirs(rootDirs) {
     for (const entry of entries) {
       if (!entry.isDirectory()) continue;
       if (entry.name === 'node_modules' || entry.name === '.git') continue;
+      // Skip `tests/fixtures/` trees: these hold reference and deliberately-
+      // malformed example modules (e.g. third-party `acme-*` skills and negative
+      // fixtures) that intentionally don't follow the production SKILL rules.
+      if (entry.name === 'fixtures' && path.basename(dir) === 'tests') continue;
 
       const fullPath = path.join(dir, entry.name);
       const skillMd = path.join(fullPath, 'SKILL.md');