ci(conformance): add 2026-07-28 carried-forward leg + bump harness to 0.2.0-alpha.4 #2783

Job	Run time
checks / pre-commit	49s
checks / readme-snippets	15s
checks / test (3.10, locked, ubuntu-latest)	1m 2s
checks / test (3.12, lowest-direct, windows-latest)	1m 27s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 4s
checks / test (3.14, lowest-direct, windows-latest)	1m 29s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 7s
checks / test (3.12, locked, windows-latest)	1m 49s
checks / test (3.10, lowest-direct, windows-latest)	1m 30s
checks / test (3.13, lowest-direct, windows-latest)	1m 52s
checks / test (3.10, locked, windows-latest)	2m 2s
checks / test (3.11, locked, ubuntu-latest)	1m 1s
checks / test (3.12, locked, ubuntu-latest)	1m 5s
checks / test (3.11, locked, windows-latest)	1m 30s
checks / test (3.11, lowest-direct, windows-latest)	1m 44s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 1s
checks / test (3.13, locked, windows-latest)	1m 46s
checks / test (3.14, locked, ubuntu-latest)	1m 44s
checks / test (3.14, lowest-direct, ubuntu-latest)	54s
checks / test (3.14, locked, windows-latest)	2m 31s
checks / test (3.13, locked, ubuntu-latest)	58s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 4s
all-green	3s
	29m 47s

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