Serve the 2026-07-28 protocol over stdio: decide the era from the opening request #3597

Job	Run time
checks / docs	49s
checks / pre-commit	48s
checks / readme-snippets	15s
checks / test (3.11, locked, windows-latest)	1m 52s
checks / test (3.10, locked, ubuntu-latest)	1m 25s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 18s
checks / test (3.10, lowest-direct, windows-latest)	1m 45s
checks / test (3.10, locked, windows-latest)	2m 5s
checks / test (3.11, lowest-direct, windows-latest)	1m 59s
checks / test (3.11, locked, ubuntu-latest)	1m 24s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 22s
checks / test (3.13, locked, windows-latest)	1m 57s
checks / test (3.14, lowest-direct, windows-latest)	1m 52s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 30s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 22s
checks / test (3.13, locked, ubuntu-latest)	1m 21s
checks / test (3.14, locked, ubuntu-latest)	1m 16s
checks / test (3.12, locked, windows-latest)	1m 40s
checks / test (3.14, locked, windows-latest)	1m 53s
checks / test (3.12, locked, ubuntu-latest)	1m 38s
checks / test (3.12, lowest-direct, windows-latest)	1m 50s
checks / test (3.13, lowest-direct, windows-latest)	2m 7s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 20s
all-green	2s
	34m 50s

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