Add SSE response mode to the 2026 streamable-HTTP server entry #3125

Job	Run time
checks / docs	41s
checks / readme-snippets	15s
checks / pre-commit	51s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.14, lowest-direct, windows-latest)	1m 48s
checks / test (3.11, locked, windows-latest)	1m 44s
checks / test (3.13, lowest-direct, windows-latest)	1m 51s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 13s
checks / test (3.11, lowest-direct, windows-latest)	1m 33s
checks / test (3.10, lowest-direct, windows-latest)	1m 39s
checks / test (3.10, locked, windows-latest)	1m 48s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 9s
checks / test (3.10, locked, ubuntu-latest)	1m 6s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 9s
checks / test (3.13, locked, ubuntu-latest)	59s
checks / test (3.12, locked, windows-latest)	1m 38s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 16s
checks / test (3.13, locked, windows-latest)	1m 34s
checks / test (3.14, locked, ubuntu-latest)	2m 11s
checks / test (3.14, locked, windows-latest)	2m 26s
checks / test (3.12, locked, ubuntu-latest)	1m 29s
checks / test (3.11, locked, ubuntu-latest)	1m 6s
checks / test (3.12, lowest-direct, windows-latest)	1m 32s
all-green	5s
	32m 3s

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