Add richer OTel MCP span attributes #1756

Job	Run time
checks / pre-commit	36s
checks / readme-snippets	11s
checks / test (3.11, lowest-direct, windows-latest)	2m 41s
checks / test (3.10, locked, ubuntu-latest)	55s
checks / test (3.12, locked, windows-latest)	3m 11s
checks / test (3.10, lowest-direct, ubuntu-latest)	59s
checks / test (3.11, lowest-direct, ubuntu-latest)	58s
checks / test (3.12, locked, ubuntu-latest)	56s
checks / test (3.11, locked, windows-latest)	2m 29s
checks / test (3.10, locked, windows-latest)	2m 21s
checks / test (3.10, lowest-direct, windows-latest)	2m 38s
checks / test (3.12, lowest-direct, ubuntu-latest)	58s
checks / test (3.11, locked, ubuntu-latest)	52s
checks / test (3.13, lowest-direct, ubuntu-latest)	52s
checks / test (3.12, lowest-direct, windows-latest)	3m 33s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 22s
checks / test (3.14, locked, windows-latest)	3m 8s
checks / test (3.13, locked, windows-latest)	2m 28s
checks / test (3.14, locked, ubuntu-latest)	2m 19s
checks / test (3.13, locked, ubuntu-latest)	50s
checks / test (3.14, lowest-direct, windows-latest)	2m 18s
checks / test (3.13, lowest-direct, windows-latest)	3m 14s
all-green	6s
	39m 55s

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