[v2] Dispatcher/ServerRunner receive-path swap — replaces BaseSession #2469

Job	Run time
checks / readme-snippets	12s
checks / pre-commit	35s
checks / test (3.13, lowest-direct, ubuntu-latest)	56s
checks / test (3.11, locked, windows-latest)	1m 19s
checks / test (3.10, locked, windows-latest)	1m 23s
checks / test (3.14, locked, ubuntu-latest)	1m 50s
checks / test (3.13, locked, windows-latest)	2m 1s
checks / test (3.11, locked, ubuntu-latest)	42s
checks / test (3.13, locked, ubuntu-latest)	43s
checks / test (3.14, lowest-direct, ubuntu-latest)	39s
checks / test (3.10, locked, ubuntu-latest)	52s
checks / test (3.10, lowest-direct, ubuntu-latest)	55s
checks / test (3.12, lowest-direct, windows-latest)	1m 30s
checks / test (3.12, lowest-direct, ubuntu-latest)	53s
checks / test (3.14, locked, windows-latest)	2m 16s
checks / test (3.14, lowest-direct, windows-latest)	1m 30s
checks / test (3.11, lowest-direct, windows-latest)	1m 38s
checks / test (3.11, lowest-direct, ubuntu-latest)	48s
checks / test (3.12, locked, ubuntu-latest)	46s
checks / test (3.10, lowest-direct, windows-latest)	1m 31s
checks / test (3.13, lowest-direct, windows-latest)	1m 22s
checks / test (3.12, locked, windows-latest)	1m 33s
all-green	5s
	25m 59s

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