* refactor(channels): flatten channel turn dispatch naming
* docs(plugin-sdk): narrow inbound reply compat guidance
* docs(channels): point stale references at turn defining modules
* fix(channels): preserve dispatch contracts after flattening
* chore(plugin-sdk): ratchet surface budgets after flattening
* chore(channels): ratchet removed export collisions
* fix(plugin-sdk): restore inbound reply compat exports
Restore eight still-existing legacy callable re-exports from canonical SDK seams and cover the deprecated package subpath with a table-driven compatibility test.
Raise the public export, callable export, and deprecated export budgets by exactly eight; the three maintainer-authorized zero-consumer symbols remain removed.
* test(channels): split channel turn kernel coverage
Replace the oversized kernel test with independently mocked delivery, pipeline, and finalize suites, preserving all 51 tests while removing the max-lines suppression and stale ratchet entry.
* chore(plugin-sdk): refresh inbound reply API hash
* fix(ci): align channel turn review fixes
Restore the test-local DeliveryResult type removed during the split.
Ratchet the public export, callable export, and deprecated export budgets by exactly seven: six channel-inbound plus one channel-outbound legacy re-export.