feat(ultraplan-local): v2.3.1 — qualified slug convention for cc-architect-catalog

Resolves v2.3.0 dogfood collision: skill-factory produced a
specialized hooks-pattern.md draft that would have overwritten the
generic seed. Qualified slugs let one feature host multiple named
patterns at different abstraction levels.

Slug convention: <cc_feature>[-<qualifier>]-<layer>.md. Unqualified =
canonical baseline. Qualified = sub-pattern (e.g., hooks-observability-
pattern.md) that does not displace the baseline.

Changes:
- SKILL.md: slug convention section, coverage-table qualified column,
  matcher logic for N patterns per feature, modification rules cover
  qualified-vs-canonical choice and collision handling.
- feature-matcher: catalog map is cc_feature -> {layer -> [skills]};
  selection rules (baseline by default, qualified when justified,
  multi-skill when non-overlapping); supporting_skill accepts list.
- gap-identifier: adds pattern_count[cc_feature] to coverage audit.
- architecture-critic: supporting-skill verification — every cited
  skill name must exist in the catalog (blocker severity).
- First qualified skill: hooks-observability-pattern.md (promoted from
  .drafts/, source ai-psychosis/README.md, ngram-overlap 0.01).
- Version bump 2.3.0 -> 2.3.1 across plugin.json, badges, table, root
  CLAUDE.md, CHANGELOG.

Non-breaking: existing unqualified slugs keep working, no cc_feature
taxonomy changes, hallucination gate unchanged.

CLAUDE.md

@@ -12,7 +12,7 @@ plugins/
   llm-security/          v6.0.0  — Security scanning, auditing, threat modeling
   ms-ai-architect/       v1.8.0  — Microsoft AI architecture (Cosmo Skyberg persona)
   okr/                   v1.0.0  — OKR guidance for Norwegian public sector
-  ultraplan-local/       v2.3.0  — Brief, research, architect, plan, execute (five-command pipeline + skill-factory Fase 1)
+  ultraplan-local/       v2.3.1  — Brief, research, architect, plan, execute (five-command pipeline + skill-factory Fase 1)
 ```
 
 Hvert plugin er selvstendig med egen CLAUDE.md, README, hooks, agents og commands.