feat(ultraplan-local): v2.2.0 — /ultra-cc-architect-local

New optional command between /ultraresearch-local and /ultraplan-local that
matches brief+research against Claude Code features (hooks, subagents, skills,
output-styles, MCP, plan-mode, worktrees, background-agents) and produces an
architecture note with brief-anchored rationale plus explicit gaps.

Added:
- commands/ultra-cc-architect-local.md (--project, --fg, --quick, --no-gaps)
- agents/architect-orchestrator.md (opus) — 6-phase background orchestrator
- agents/feature-matcher.md (sonnet) — fallback-ranked feature proposals
- agents/gap-identifier.md (sonnet) — 4 gap classes with issue-ready drafts
- agents/architecture-critic.md (sonnet) — hallucination gate as BLOCKER
- skills/cc-architect-catalog/ — SKILL.md + 10 seed entries (reference/pattern)

Changed (non-breaking):
- commands/ultraplan-local.md — auto-discovers architecture/overview.md
- agents/planning-orchestrator.md — cross-references cc_features_proposed
- plugin.json — 2.1.0 → 2.2.0, description, cc-architecture keyword
- CHANGELOG, README, CLAUDE.md (plugin + marketplace root)

Pipeline becomes brief → research → architect → plan → execute. Architect is
optional; existing project dirs keep working unchanged.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

plugins/ultraplan-local/skills/cc-architect-catalog/skills-reference.md

@@ -0,0 +1,83 @@
+---
+name: skills-reference
+description: CC skills — auto-invoked domain modules with SKILL.md, frontmatter triggers, and file-hierarchy discovery.
+layer: reference
+cc_feature: skills
+source: https://docs.claude.com/en/docs/claude-code/skills
+concept: skills-system
+last_verified: 2026-04-18
+ngram_overlap_score: null
+review_status: approved
+---
+
+# Skills — Reference
+
+Claude Code's skill system is a way to package domain knowledge,
+workflows, and supporting files so Claude can load them on demand. A
+skill is a directory with a `SKILL.md` manifest and any auxiliary
+files (scripts, templates, references).
+
+## Anatomy
+
+- **`SKILL.md`** — the entry point. Markdown file with YAML
+  frontmatter and a body. The frontmatter declares when the skill
+  triggers; the body is instructions Claude follows after loading.
+- **Auxiliary files** — any files in the skill directory. Loaded on
+  demand (typically by Claude reading them when the body references
+  them). Common: `scripts/`, `templates/`, `references/`.
+
+## Frontmatter
+
+```yaml
+---
+name: <skill-name>
+description: <one-line trigger hint>
+---
+```
+
+The `description` is what Claude sees when deciding whether to invoke.
+It should describe *when* to use the skill, not *what* it does.
+
+## Invocation
+
+- **Auto-invocation** — Claude loads the skill when the user's prompt
+  matches the description's triggers. The trigger model is implicit
+  (natural-language match), not regex.
+- **Manual invocation** — the user types `/<skill-name>` and Claude
+  calls the Skill tool.
+- **Never auto-invoked** — if the description explicitly says so
+  ("Internal catalog for X — not invoked directly"), Claude typically
+  respects the hint.
+
+## Discovery
+
+Skills are discovered from:
+
+- **Built-in skills** — shipped with the CLI.
+- **Plugin skills** — packaged inside a plugin's `skills/` directory.
+- **User skills** — `~/.claude/skills/`.
+- **Project skills** — `.claude/skills/` inside the repo.
+
+The CLI surfaces available skills via `--allowedTools` and in the
+system prompt.
+
+## Progressive disclosure
+
+Skills use progressive disclosure:
+
+1. Claude sees only the name + description at session start.
+2. When a skill triggers, the body loads into context.
+3. Files referenced by the body load only when Claude reads them.
+
+This keeps the baseline context small; depth is paid for on demand.
+
+## Relationship to other features
+
+- **Skills vs subagents** — a skill lives in the parent's context when
+  loaded. A subagent runs in its own context. Choose skill when the
+  context flows through; subagent when it should not.
+- **Skills vs hooks** — hooks are deterministic harness-level rules.
+  Skills are context that Claude interprets. A skill cannot enforce;
+  only guide.
+- **Skills vs MCP** — MCP exposes *tools*. Skills are *knowledge*. An
+  MCP tool + a skill that explains when to use it is a common pairing.