docs: add coverage verification instruction to CLAUDE.md #679

Job	Run time
checks / pre-commit	33s
checks / readme-snippets	12s
checks / test (3.11, lowest-direct, windows-latest)	3m 24s
checks / test (3.10, locked, windows-latest)	2m 16s
checks / test (3.12, lowest-direct, ubuntu-latest)	58s
checks / test (3.10, lowest-direct, windows-latest)	3m 20s
checks / test (3.13, locked, windows-latest)	2m 33s
checks / test (3.11, locked, windows-latest)	2m 44s
checks / test (3.10, locked, ubuntu-latest)	52s
checks / test (3.13, locked, ubuntu-latest)	46s
checks / test (3.11, locked, ubuntu-latest)	51s
checks / test (3.13, lowest-direct, ubuntu-latest)	51s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 20s
checks / test (3.12, locked, ubuntu-latest)	58s
checks / test (3.12, lowest-direct, windows-latest)	3m 42s
checks / test (3.12, locked, windows-latest)	3m 44s
checks / test (3.13, lowest-direct, windows-latest)	2m 59s
checks / test (3.14, lowest-direct, windows-latest)	3m 21s
checks / test (3.11, lowest-direct, ubuntu-latest)	56s
checks / test (3.14, locked, ubuntu-latest)	2m 22s
checks / test (3.10, lowest-direct, ubuntu-latest)	52s
checks / test (3.14, locked, windows-latest)	5m 11s
all-green	5s
	44m 50s

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