feat: add GNS3 Copilot AI agent dependencies to requirements

Add comprehensive dependencies for the new GNS3 Copilot AI agent feature. This includes:
- Core AI and automation frameworks (LangChain, LangGraph)
- Multiple model provider integrations (OpenAI, Anthropic, Google, AWS, Ollama, DeepSeek, xAI)
- Network automation tools (Netmiko, Nornir)
- Supporting libraries for telnet, HTTP requests, authentication, and image processing

The dependencies are organized into a dedicated section with clear comments for maintainability.

requirements.txt

@@ -1,3 +1,4 @@
+# GNS3 Server Core Dependencies
 uvicorn==0.39.0; python_version == '3.9'  # version 0.39.0 is the last version supporting Python 3.9
 uvicorn==0.41.0; python_version >= '3.10'
 pydantic==2.12.5
@@ -26,3 +27,52 @@ watchdog==6.0.0
 zstandard==0.25.0
 platformdirs>=2.4.0,<3  # platformdirs >=3 conflicts when building Debian packages
 truststore>=0.10.4; python_version >= '3.10'
+
+# ==============================================================================
+# GNS3 Copilot AI Agent Dependencies
+# ==============================================================================
+
+# Core AI and Automation Framework
+aiosqlite>=0.19.0
+langchain>=1.2.0
+langchain-core>=1.2.6
+langgraph>=1.0.5
+langgraph-checkpoint-sqlite>=3.0.1
+langgraph-checkpoint-postgres>=2.0.0
+
+# Model Providers
+langchain-openai>=1.1.6
+langchain-anthropic>=1.3.1
+langchain-google-genai>=4.1.3
+langchain-aws>=1.2.0
+langchain-ollama>=1.0.1
+langchain-deepseek>=1.0.1
+langchain-xai>=1.2.1
+
+# Network Automation
+netmiko>=4.6.0
+nornir>=3.5.0
+nornir-netmiko>=1.0.1
+nornir-utils>=0.2.0
+nornir-salt>=0.23.0
+
+# Telnet Client
+telnetlib3>=2.0.8
+
+# Environment & Configuration
+python-dotenv>=1.2.1
+
+# HTTP Requests
+requests>=2.32.5
+urllib3>=2.6.2
+httpx>=0.27.0
+
+# Authentication
+PyJWT>=2.10.1
+psycopg-pool>=3.1.0
+
+# Type Extensions
+typing-extensions>=4.15.0
+
+# Image Processing
+Pillow>=10.0.0