Make AI features (AI Copilot + MCP) optional via [ai-features] extra

- Move fastmcp from core requirements.txt to mcp-requirements.txt
- Add MCP_AVAILABLE feature flag in agent/__init__.py (graceful degradation)
- Guard MCP imports/registration in server.py and tasks.py
- Replace ai-copilot/mcp/ai-support extras with single ai-features extra
- Add stub MCP routes returning 501 when MCP is not installed
- Add gns3server-uninstall-ai-features CLI command
- Remove old gns3server-uninstall-ai-copilot command
- Update all error messages and docs to reference ai-features

Closes #2794

gns3server/utils/uninstall_ai_features.py

@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+"""
+Uninstall AI Features dependencies (AI Copilot + MCP).
+
+Usage:
+    gns3server-uninstall-ai-features
+    gns3server-uninstall-ai-features -y
+"""
+
+import os
+import sys
+import subprocess
+import argparse
+
+
+def _find_base_dir():
+    """Find the project root directory."""
+    if hasattr(sys, '_MEIPASS'):
+        return os.path.dirname(sys.executable)
+    return os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+
+def _read_requirements(filename):
+    """Read packages from a requirements file."""
+    base_dir = _find_base_dir()
+    filepath = os.path.join(base_dir, filename)
+    packages = []
+    with open(filepath, "r") as f:
+        for line in f:
+            line = line.strip()
+            if not line or line.startswith("#"):
+                continue
+            package = line.split(">=")[0].split("==")[0].split("~=")[0]
+            packages.append(package)
+    return packages
+
+
+def get_ai_packages():
+    """Read packages from all AI features requirements files."""
+    packages = []
+    packages.extend(_read_requirements("ai-requirements.txt"))
+    packages.extend(_read_requirements("mcp-requirements.txt"))
+    # Remove duplicates while preserving order
+    seen = set()
+    unique = []
+    for pkg in packages:
+        if pkg not in seen:
+            seen.add(pkg)
+            unique.append(pkg)
+    return unique
+
+
+def uninstall(packages, yes=False):
+    """Uninstall packages."""
+    if not packages:
+        print("No packages found to uninstall.")
+        return
+
+    print(f"Found {len(packages)} AI Features dependencies:")
+    for pkg in packages:
+        print(f"  - {pkg}")
+    print()
+
+    if not yes:
+        response = input("Do you want to uninstall these packages? [y/N]: ")
+        if response.lower() != "y":
+            print("Cancelled.")
+            return
+
+    print("Uninstalling...")
+    for package in packages:
+        try:
+            result = subprocess.run(
+                [sys.executable, "-m", "pip", "uninstall", "-y", package],
+                capture_output=True,
+                text=True
+            )
+            if result.returncode == 0:
+                print(f"  Removed: {package}")
+            else:
+                print(f"  Failed to remove {package} (may not be installed)")
+        except Exception as e:
+            print(f"  Error removing {package}: {e}")
+
+    print("\nAI Features dependencies have been uninstalled.")
+    print("You can reinstall them with: pip install gns3-server[ai-features]")
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Uninstall AI Features dependencies (AI Copilot + MCP)"
+    )
+    parser.add_argument(
+        "-y", "--yes", action="store_true",
+        help="Automatically confirm uninstallation"
+    )
+    args = parser.parse_args()
+
+    packages = get_ai_packages()
+    uninstall(packages, yes=args.yes)
+
+
+if __name__ == "__main__":
+    main()