auto-claude: subtask-4-1 - Add DEEPSEEK_API_KEY and SUPABASE_SERVICE_ROLE_KEY

- Created .env.example with template for all environment variables
- Added DEEPSEEK_API_KEY for DeepSeek API integration
- Added SUPABASE_SERVICE_ROLE_KEY for server-side Supabase operations
- Updated .env.local with placeholder values (not committed due to .gitignore)

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

.env.example

@@ -0,0 +1,13 @@
+# Supabase
+NEXT_PUBLIC_SUPABASE_URL=your_supabase_url
+NEXT_PUBLIC_SUPABASE_ANON_KEY=your_supabase_anon_key
+SUPABASE_SERVICE_ROLE_KEY=your_supabase_service_role_key
+
+# DeepSeek API
+DEEPSEEK_API_KEY=your_deepseek_api_key
+
+# Analytics
+NEXT_PUBLIC_GA_TRACKING_ID=your_ga_tracking_id
+
+# Site URL
+NEXT_PUBLIC_SITE_URL=https://your-domain.com