Add SSE response mode to the 2026 streamable-HTTP server entry (#3001) #3129

Job	Run time
checks / pre-commit	46s
checks / readme-snippets	12s
checks / docs	42s
checks / test (3.11, lowest-direct, windows-latest)	1m 39s
checks / test (3.10, lowest-direct, windows-latest)	1m 39s
checks / test (3.11, locked, windows-latest)	1m 54s
checks / test (3.10, locked, ubuntu-latest)	1m 16s
checks / test (3.12, lowest-direct, windows-latest)	1m 33s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 13s
checks / test (3.13, locked, ubuntu-latest)	1m 3s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 9s
checks / test (3.12, locked, ubuntu-latest)	1m 21s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 8s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 12s
checks / test (3.11, locked, ubuntu-latest)	1m 9s
checks / test (3.10, locked, windows-latest)	1m 44s
checks / test (3.12, locked, windows-latest)	1m 44s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.14, locked, windows-latest)	2m 45s
checks / test (3.14, lowest-direct, windows-latest)	1m 37s
checks / test (3.13, locked, windows-latest)	1m 41s
checks / test (3.13, lowest-direct, windows-latest)	2m 0s
checks / test (3.14, locked, ubuntu-latest)	2m 10s
all-green	3s
	32m 40s

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