Restore mcp.server.fastmcp as a deprecated import alias for MCPServer #3692

Job	Run time
checks / readme-snippets	14s
checks / pre-commit	1m 0s
checks / docs	1m 5s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 29s
checks / test (3.13, locked, ubuntu-latest)	1m 18s
checks / test (3.12, locked, ubuntu-latest)	1m 38s
checks / test (3.14, locked, ubuntu-latest)	1m 18s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 1s
checks / test (3.11, locked, ubuntu-latest)	1m 25s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 19s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 32s
checks / test (3.10, locked, windows-latest)	1m 54s
checks / test (3.11, locked, windows-latest)	2m 2s
checks / test (3.13, locked, windows-latest)	1m 54s
checks / test (3.10, locked, ubuntu-latest)	1m 30s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 18s
checks / test (3.11, lowest-direct, windows-latest)	1m 53s
checks / test (3.13, lowest-direct, windows-latest)	1m 54s
checks / test (3.14, locked, windows-latest)	2m 10s
checks / test (3.10, lowest-direct, windows-latest)	1m 52s
checks / test (3.12, locked, windows-latest)	1m 57s
checks / test (3.12, lowest-direct, windows-latest)	2m 2s
checks / test (3.14, lowest-direct, windows-latest)	2m 13s
all-green	3s
	36m 1s

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