Rename `FastMCP` to `MCPServer` #365

Job	Run time
checks / readme-snippets	13s
checks / pre-commit	31s
checks / test (3.10, lowest-direct, windows-latest)	2m 33s
checks / test (3.10, locked, ubuntu-latest)	48s
checks / test (3.11, lowest-direct, windows-latest)	2m 49s
checks / test (3.11, locked, ubuntu-latest)	48s
checks / test (3.11, locked, windows-latest)	2m 32s
checks / test (3.10, locked, windows-latest)	2m 21s
checks / test (3.10, lowest-direct, ubuntu-latest)	51s
checks / test (3.12, lowest-direct, ubuntu-latest)	58s
checks / test (3.14, lowest-direct, windows-latest)	2m 9s
checks / test (3.13, lowest-direct, windows-latest)	2m 40s
checks / test (3.11, lowest-direct, ubuntu-latest)	55s
checks / test (3.12, lowest-direct, windows-latest)	4m 18s
checks / test (3.13, locked, windows-latest)	2m 40s
checks / test (3.12, locked, windows-latest)	3m 53s
checks / test (3.12, locked, ubuntu-latest)	51s
checks / test (3.14, locked, windows-latest)	3m 17s
checks / test (3.13, locked, ubuntu-latest)	48s
checks / test (3.14, locked, ubuntu-latest)	2m 18s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 17s
checks / test (3.13, lowest-direct, ubuntu-latest)	51s
all-green	5s
	40m 26s

Provide feedback