fix(streamable-http): expose session_idle_timeout and pause idle reaping during active requests #1882

Job	Run time
checks / pre-commit	34s
checks / readme-snippets	14s
checks / test (3.10, lowest-direct, ubuntu-latest)	55s
checks / test (3.10, locked, ubuntu-latest)	48s
checks / test (3.10, lowest-direct, windows-latest)	2m 39s
checks / test (3.10, locked, windows-latest)	2m 39s
checks / test (3.11, lowest-direct, ubuntu-latest)	58s
checks / test (3.11, locked, ubuntu-latest)	49s
checks / test (3.11, locked, windows-latest)	3m 39s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 5s
checks / test (3.11, lowest-direct, windows-latest)	2m 45s
checks / test (3.13, lowest-direct, windows-latest)	2m 37s
checks / test (3.12, locked, windows-latest)	3m 31s
checks / test (3.12, lowest-direct, windows-latest)	3m 22s
checks / test (3.13, locked, ubuntu-latest)	46s
checks / test (3.14, locked, ubuntu-latest)	2m 33s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 19s
checks / test (3.13, lowest-direct, ubuntu-latest)	57s
checks / test (3.14, locked, windows-latest)	3m 49s
checks / test (3.14, lowest-direct, windows-latest)	2m 22s
checks / test (3.12, locked, ubuntu-latest)	1m 2s
checks / test (3.13, locked, windows-latest)	2m 30s
all-green	4s
	41m 57s

Provide feedback