refactor: update environment configuration, enhance installation script, and add migration scripts for database setup

.env.example

@@ -1,14 +1,23 @@
-# ─── Supabase (Zorunlu) ───────────────────────────────────────
-NEXT_PUBLIC_SUPABASE_URL=your_supabase_url
-NEXT_PUBLIC_SUPABASE_ANON_KEY=your_supabase_anon_key
+# Neta self-host environment
 
-# Müşteri Portalı hesabı oluşturmak için gerekli (Freelancer panelinde kullanılır)
-SUPABASE_SERVICE_ROLE_KEY=your_supabase_service_role_key
+# Public URL where users open Neta.
+NEXT_PUBLIC_SITE_URL=http://localhost:3000
 
-# ─── AI Sağlayıcılar (Opsiyonel — uygulama içi ayarlardan da tanımlanabilir) ───
-# OPENAI_API_KEY=your_openai_api_key
-# GROQ_API_KEY=your_groq_api_key
-# GEMINI_API_KEY=your_gemini_api_key
+# Host port mapped to the Neta container's internal port 3000.
+NETA_PORT=3000
 
-# ─── Supabase Auth (Self-host'ta gerekli olabilir) ───────────
-# NEXT_PUBLIC_SITE_URL=https://neta.example.com
+# Supabase API URL. For a hosted project this looks like:
+# https://your-project.supabase.co
+# For a bundled/self-hosted Supabase setup this is usually your public API URL.
+NEXT_PUBLIC_SUPABASE_URL=
+
+# Supabase anon/public API key.
+NEXT_PUBLIC_SUPABASE_ANON_KEY=
+
+# Supabase service role key. Required for creating client portal accounts.
+# Keep this secret. It is only used server-side.
+SUPABASE_SERVICE_ROLE_KEY=
+
+# Optional: direct Postgres connection string used only by bash ./scripts/apply-migrations.sh.
+# Do not expose this to browsers. It is not required by the web container.
+# DATABASE_URL=postgresql://postgres:password@host:5432/postgres