[v2] Dispatcher/ServerRunner receive-path swap — replaces BaseSession #2505

Job	Run time
checks / readme-snippets	15s
checks / test (3.13, locked, ubuntu-latest)	51s
checks / test (3.10, lowest-direct, windows-latest)	1m 23s
checks / test (3.14, lowest-direct, windows-latest)	1m 12s
checks / test (3.12, locked, ubuntu-latest)	56s
checks / test (3.10, locked, windows-latest)	1m 24s
checks / test (3.13, lowest-direct, ubuntu-latest)	49s
checks / test (3.11, lowest-direct, windows-latest)	2m 10s
checks / test (3.12, lowest-direct, ubuntu-latest)	54s
checks / test (3.12, lowest-direct, windows-latest)	1m 24s
checks / test (3.11, lowest-direct, ubuntu-latest)	52s
checks / test (3.11, locked, windows-latest)	1m 15s
checks / test (3.14, locked, ubuntu-latest)	1m 58s
checks / test (3.12, locked, windows-latest)	1m 28s
checks / test (3.14, lowest-direct, ubuntu-latest)	52s
checks / test (3.14, locked, windows-latest)	2m 44s
checks / test (3.13, lowest-direct, windows-latest)	1m 27s
checks / test (3.13, locked, windows-latest)	1m 40s
checks / test (3.11, locked, ubuntu-latest)	51s
checks / test (3.10, locked, ubuntu-latest)	57s
checks / test (3.10, lowest-direct, ubuntu-latest)	53s
checks / pre-commit	36s
all-green	5s
	26m 56s

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