[v2] Dispatcher/ServerRunner receive-path swap — replaces BaseSession #2504

Job	Run time
checks / pre-commit	29s
checks / readme-snippets	10s
checks / test (3.10, lowest-direct, windows-latest)	1m 14s
checks / test (3.10, locked, windows-latest)	1m 17s
checks / test (3.11, lowest-direct, windows-latest)	1m 19s
checks / test (3.10, lowest-direct, ubuntu-latest)	53s
checks / test (3.11, locked, windows-latest)	1m 15s
checks / test (3.13, lowest-direct, ubuntu-latest)	51s
checks / test (3.12, locked, ubuntu-latest)	53s
checks / test (3.11, locked, ubuntu-latest)	32s
checks / test (3.12, locked, windows-latest)	1m 20s
checks / test (3.14, lowest-direct, ubuntu-latest)	52s
checks / test (3.12, lowest-direct, ubuntu-latest)	54s
checks / test (3.11, lowest-direct, ubuntu-latest)	41s
checks / test (3.14, lowest-direct, windows-latest)	1m 11s
checks / test (3.14, locked, windows-latest)	2m 6s
checks / test (3.12, lowest-direct, windows-latest)	1m 22s
checks / test (3.13, locked, windows-latest)	1m 23s
checks / test (3.10, locked, ubuntu-latest)	50s
checks / test (3.13, lowest-direct, windows-latest)	1m 32s
checks / test (3.14, locked, ubuntu-latest)	1m 51s
checks / test (3.13, locked, ubuntu-latest)	47s
all-green	2s
	23m 44s

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