Add everything-server for comprehensive MCP conformance testing #3257

Job	Run time
checks / pre-commit	27s
checks / readme-snippets	10s
checks / test (3.10, lowest-direct, windows-latest)	1m 59s
checks / test (3.10, highest, ubuntu-latest)	34s
checks / test (3.11, lowest-direct, ubuntu-latest)	37s
checks / test (3.10, lowest-direct, ubuntu-latest)	37s
checks / test (3.11, highest, windows-latest)	1m 41s
checks / test (3.12, lowest-direct, windows-latest)	1m 35s
checks / test (3.11, lowest-direct, windows-latest)	1m 36s
checks / test (3.12, highest, ubuntu-latest)	31s
checks / test (3.10, highest, windows-latest)	1m 58s
checks / test (3.13, lowest-direct, ubuntu-latest)	37s
checks / test (3.12, lowest-direct, ubuntu-latest)	36s
checks / test (3.13, highest, ubuntu-latest)	36s
checks / test (3.11, highest, ubuntu-latest)	34s
checks / test (3.13, highest, windows-latest)	1m 29s
checks / test (3.13, lowest-direct, windows-latest)	1m 39s
checks / test (3.12, highest, windows-latest)	1m 34s
	18m 50s

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