chore: import upstream snapshot with attribution

.env.example

@@ -0,0 +1,24 @@
+# ============================================================================
+# LLM Provider Configuration
+# ============================================================================
+# BASE_URL and API_KEY are the standard configurations for model call authentication.
+# These variables support OpenAI, Gemini, LM Studio, Ollama, and other providers.
+
+BASE_URL=https://api.openai.com/v1
+API_KEY=sk-your-openai-api-key-here
+
+# Example BASE_URL values:
+# - OpenAI:    https://api.openai.com/v1
+# - Gemini:    https://generativelanguage.googleapis.com
+# - LM Studio: http://localhost:1234/v1
+# - Ollama:    http://localhost:11434/v1
+
+# ============================================================================
+# Optional: Web Search and Reading Tools
+# ============================================================================
+
+# SERPER_DEV_API_KEY=your-serper-api-key-here
+# Get from: https://serper.dev
+
+# JINA_API_KEY=your-jina-api-key-here
+# Get from: https://jina.ai