refactor: update env example

.env.example

@@ -0,0 +1,38 @@
+# Application settings
+APP_NAME=ValueCell
+APP_VERSION=0.1.0
+APP_ENVIRONMENT=development
+API_DEBUG=true
+
+# API settings
+API_ENABLED=true
+API_I18N_ENABLED=true
+API_HOST=localhost
+API_PORT=8000
+
+# Ensure UTF-8 encoding
+LANG=en_US.UTF-8
+TIMEZONE=America/New_York
+
+# Agent Settings
+AGENT_DEBUG_MODE=false
+
+# Model Provider settings
+# Get your key from: https://openrouter.ai/
+OPENROUTER_API_KEY=
+
+# Model IDs for OpenRouter
+PLANNER_MODEL_ID=google/gemini-2.5-pro
+SEC_PARSER_MODEL_ID=openai/gpt-4o-mini
+SEC_ANALYSIS_MODEL_ID=deepseek/deepseek-chat-v3-0324
+AI_HEDGE_FUND_PARSER_MODEL_ID=google/gemini-2.5-flash
+
+# SEC Agent Configurations
+# Email address for SEC API requests (required by SEC)
+SEC_EMAIL=
+
+# TradingAgents Configurations
+# refer to ./python/third_party/TradingAgents/.env.example for details
+# OpenAI API Key - Required for LLM models and online data search
+# Get your key from: https://platform.openai.com/api-keys
+# OPENAI_API_KEY=