chore: post-merge sync — statistical-analyst plugin, spec-to-repo skill, docs update

New:
- feat(product-team): add spec-to-repo skill — natural-language spec to runnable repo
  1 Python tool (validate_project.py), 2 references, 3 concrete examples
- feat(engineering): add statistical-analyst plugin.json + marketplace entry (32 total)

Sync:
- Update all counts to 233 skills, 305 tools, 424 refs, 25 agents, 22 commands
- Fix engineering-advanced plugin description: 42 → 43 skills
- Sync Codex (194 skills), Gemini (282 items), MkDocs (281 pages → 313 HTML)
- Update CLAUDE.md, README.md, docs/index.md, docs/getting-started.md, mkdocs.yml
- Expand product-analytics SKILL.md + add JSON output to metrics_calculator.py

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gemini/skills-index.json

@@ -1,7 +1,7 @@
 {
   "version": "1.0.0",
   "name": "gemini-cli-skills",
-  "total_skills": 280,
+  "total_skills": 282,
   "skills": [
     {
       "name": "README",
@@ -958,6 +958,11 @@
       "category": "engineering-advanced",
       "description": "Use when the user asks to write SQL queries, optimize database performance, generate migrations, explore database schemas, or work with ORMs like Prisma, Drizzle, TypeORM, or SQLAlchemy."
     },
+    {
+      "name": "statistical-analyst",
+      "category": "engineering-advanced",
+      "description": "Run hypothesis tests, analyze A/B experiment results, calculate sample sizes, and interpret statistical significance with effect sizes. Use when you need to validate whether observed differences are real, size an experiment correctly before launch, or interpret test results with confidence."
+    },
     {
       "name": "tech-debt-tracker",
       "category": "engineering-advanced",
@@ -1278,6 +1283,11 @@
       "category": "product",
       "description": "Generates complete, production-ready SaaS project boilerplate including authentication, database schemas, billing integration, API routes, and a working dashboard using Next.js 14+ App Router, TypeScript, Tailwind CSS, shadcn/ui, Drizzle ORM, and Stripe. Use when the user wants to create a new SaaS app, start a subscription-based web project, scaffold a Next.js application, or mentions terms like starter template, boilerplate, new project, or wiring up auth and payments."
     },
+    {
+      "name": "spec-to-repo",
+      "category": "product",
+      "description": "Use when the user says 'build me an app', 'create a project from this spec', 'scaffold a new repo', 'generate a starter', 'turn this idea into code', 'bootstrap a project', 'I have requirements and need a codebase', or provides a natural-language project specification and expects a complete, runnable repository. Stack-agnostic: Next.js, FastAPI, Rails, Go, Rust, Flutter, and more."
+    },
     {
       "name": "ui-design-system",
       "category": "product",
@@ -1426,7 +1436,7 @@
       "description": "Engineering resources"
     },
     "engineering-advanced": {
-      "count": 56,
+      "count": 57,
       "description": "Engineering-advanced resources"
     },
     "finance": {
@@ -1438,7 +1448,7 @@
       "description": "Marketing resources"
     },
     "product": {
-      "count": 15,
+      "count": 16,
       "description": "Product resources"
     },
     "project-management": {

.gemini/skills/spec-to-repo/SKILL.md

@@ -0,0 +1 @@
+../../../product-team/spec-to-repo/SKILL.md

.gemini/skills/statistical-analyst/SKILL.md

@@ -0,0 +1 @@
+../../../engineering/statistical-analyst/SKILL.md