feat: turbostarter boilerplate

Production-ready Next.js boilerplate with:
- Runtime env validation (fail-fast on missing vars)
- Feature-gated config (S3, Stripe, email, OAuth)
- Docker + Coolify deployment pipeline
- PostgreSQL + pgvector, MinIO S3, Better Auth
- TypeScript strict mode (no ignoreBuildErrors)
- i18n (en/es), AI modules, billing, monitoring

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.env.production.example

@@ -0,0 +1,136 @@
+# ============================================================
+# PRODUCTION ENVIRONMENT VARIABLES
+# ============================================================
+# Copy this file and fill in your values:
+#   cp .env.production.example .env.production
+#
+# Legend:
+#   [REQUIRED]  — App will NOT start without this
+#   [FEATURE]   — Required only when the feature is enabled
+#   [OPTIONAL]  — Has a sensible default, override if needed
+# ============================================================
+
+# ── CORE (REQUIRED) ──────────────────────────────────────────
+
+# PostgreSQL connection string
+# [REQUIRED] App crashes immediately without this
+DATABASE_URL="postgresql://user:password@host:5432/dbname"
+
+# Secret for signing auth sessions/tokens
+# [REQUIRED] Generate with: openssl rand -base64 32
+BETTER_AUTH_SECRET=""
+
+# Public URL of the app (used for OAuth callbacks, email links, OG meta)
+# [REQUIRED] Set at BUILD TIME via --build-arg NEXT_PUBLIC_URL=...
+NEXT_PUBLIC_URL="https://your-app.example.com"
+
+# Comma-separated list of allowed origins for CSRF protection
+# [REQUIRED] Must include your public URL
+BETTER_AUTH_TRUSTED_ORIGINS="https://your-app.example.com"
+
+# ── PRODUCT ──────────────────────────────────────────────────
+
+# [OPTIONAL] App display name (default: "TurboStarter")
+NEXT_PUBLIC_PRODUCT_NAME="MyApp"
+
+# [OPTIONAL] Contact email shown in the app
+CONTACT_EMAIL="hello@example.com"
+
+# [OPTIONAL] Default locale (default: "en")
+NEXT_PUBLIC_DEFAULT_LOCALE="en"
+
+# [OPTIONAL] Theme mode: "light" | "dark" | "system" (default: "system")
+NEXT_PUBLIC_THEME_MODE="system"
+
+# [OPTIONAL] Theme color (default: "orange")
+NEXT_PUBLIC_THEME_COLOR="orange"
+
+# ── AUTH METHODS ─────────────────────────────────────────────
+
+# [OPTIONAL] Toggle auth methods (default shown)
+NEXT_PUBLIC_AUTH_PASSWORD=true
+NEXT_PUBLIC_AUTH_MAGIC_LINK=false
+NEXT_PUBLIC_AUTH_PASSKEY=true
+NEXT_PUBLIC_AUTH_ANONYMOUS=true
+
+# [OPTIONAL] Signup credits (default: 100 in production)
+FREE_TIER_CREDITS=100
+
+# Seed user for initial setup
+SEED_EMAIL="admin@example.com"
+SEED_PASSWORD="ChangeThisPassword!"
+
+# ── OAUTH PROVIDERS ──────────────────────────────────────────
+# Leave empty to disable the provider (login button won't show)
+
+# [FEATURE] Google OAuth
+GOOGLE_CLIENT_ID=""
+GOOGLE_CLIENT_SECRET=""
+
+# [FEATURE] GitHub OAuth
+GITHUB_CLIENT_ID=""
+GITHUB_CLIENT_SECRET=""
+
+# [FEATURE] Apple OAuth
+APPLE_CLIENT_ID=""
+APPLE_CLIENT_SECRET=""
+APPLE_APP_BUNDLE_IDENTIFIER=""
+
+# ── S3 STORAGE ───────────────────────────────────────────────
+# Set S3_BUCKET to enable. All other S3 vars become required.
+
+# [FEATURE] S3-compatible storage (MinIO, AWS S3, R2, etc.)
+S3_BUCKET=""
+S3_REGION="us-east-1"
+S3_ENDPOINT="http://minio:9000"
+S3_ACCESS_KEY_ID=""
+S3_SECRET_ACCESS_KEY=""
+
+# ── BILLING (STRIPE) ────────────────────────────────────────
+# Set STRIPE_SECRET_KEY to enable. Webhook secret becomes required.
+
+# [FEATURE] Stripe payments
+STRIPE_SECRET_KEY=""
+STRIPE_WEBHOOK_SECRET=""
+
+# [OPTIONAL] Billing model: "recurring" | "one_time" | "credits"
+BILLING_MODEL="recurring"
+
+# ── EMAIL ────────────────────────────────────────────────────
+# Configure ONE email provider. Set the API key to enable.
+
+# [FEATURE] Resend (recommended)
+RESEND_API_KEY=""
+
+# [FEATURE] OR Nodemailer (self-hosted SMTP)
+# NODEMAILER_HOST=""
+# NODEMAILER_PORT="465"
+# NODEMAILER_USER=""
+# NODEMAILER_PASSWORD=""
+
+# [FEATURE] Sender address (required when any email provider is configured)
+EMAIL_FROM="noreply@yourdomain.com"
+
+# ── MONITORING ───────────────────────────────────────────────
+# All monitoring is optional. App works fine without it.
+
+# [OPTIONAL] Sentry error tracking
+NEXT_PUBLIC_SENTRY_DSN=""
+
+# [OPTIONAL] PostHog analytics
+NEXT_PUBLIC_POSTHOG_KEY=""
+NEXT_PUBLIC_POSTHOG_HOST="https://us.i.posthog.com"
+
+# ── AI (if using AI features) ───────────────────────────────
+
+# [FEATURE] OpenAI
+# OPENAI_API_KEY=""
+
+# [FEATURE] Anthropic
+# ANTHROPIC_API_KEY=""
+
+# [FEATURE] ElevenLabs TTS
+# ELEVENLABS_API_KEY=""
+
+# [FEATURE] Tavily search
+# TAVILY_API_KEY=""