refactor: Update FastMCP examples to use new import path

Update all FastMCP examples to use mcp.server.fastmcp instead of fastmcp.
Add tests to verify example servers work correctly.

Changes:
- Update import paths in all example files
- Create test_examples.py to verify functionality
- Fix test assertions to match actual response format

examples/fastmcp/screenshot.py

@@ -0,0 +1,29 @@
+"""
+FastMCP Screenshot Example
+
+Give Claude a tool to capture and view screenshots.
+"""
+
+import io
+from mcp.server.fastmcp import FastMCP
+from mcp.server.fastmcp.utilities.types import Image
+
+
+# Create server
+mcp = FastMCP("Screenshot Demo", dependencies=["pyautogui", "Pillow"])
+
+
+@mcp.tool()
+def take_screenshot() -> Image:
+    """
+    Take a screenshot of the user's screen and return it as an image. Use
+    this tool anytime the user wants you to look at something they're doing.
+    """
+    import pyautogui
+
+    buffer = io.BytesIO()
+
+    # if the file exceeds ~1MB, it will be rejected by Claude
+    screenshot = pyautogui.screenshot()
+    screenshot.convert("RGB").save(buffer, format="JPEG", quality=60, optimize=True)
+    return Image(data=buffer.getvalue(), format="jpeg")