Add richer OTel MCP span attributes #1755

Job	Run time
checks / pre-commit	33s
checks / readme-snippets	15s
checks / test (3.11, lowest-direct, windows-latest)	3m 18s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.11, locked, ubuntu-latest)	51s
checks / test (3.10, locked, windows-latest)	2m 36s
checks / test (3.10, lowest-direct, windows-latest)	2m 41s
checks / test (3.11, lowest-direct, ubuntu-latest)	55s
checks / test (3.10, lowest-direct, ubuntu-latest)	55s
checks / test (3.12, locked, windows-latest)	4m 12s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 2s
checks / test (3.11, locked, windows-latest)	2m 16s
checks / test (3.14, locked, windows-latest)	3m 15s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 18s
checks / test (3.13, locked, ubuntu-latest)	52s
checks / test (3.10, locked, ubuntu-latest)	50s
checks / test (3.12, lowest-direct, windows-latest)	4m 11s
checks / test (3.12, locked, ubuntu-latest)	55s
checks / test (3.14, lowest-direct, windows-latest)	2m 24s
checks / test (3.14, locked, ubuntu-latest)	2m 20s
checks / test (3.13, locked, windows-latest)	2m 55s
checks / test (3.13, lowest-direct, windows-latest)	2m 46s
all-green	4s
	42m 24s

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