The local --channel command no longer touches R2: it resolves the exact
pushed commit and dispatches the default-branch workflow, whose privileged
allocation step creates the channel and mints the immutable build request.
The disposable allocation path is generalized to cover the unscoped
production preview, gated by a new `channel` workflow input; build legs
consume the same channel-build / channel-request-sha256 job outputs as
before. The anti-tamper gate is now commit_build.admit (maintainer
permission) running inside the allocate step.
Drop the resume path: --resume-channel-build / --request-sha256 and
resume_build() are gone, and allocate_protected no longer recovers a lost
request PUT by sequence. Retrying re-dispatches and mints a fresh sequence
slot; idempotency survives via the deterministic build ID and the existing
immutable-request dedup. Keep the preview allocate `lastAllocation` build-ID
field (concurrent-CAS uniqueness), which is not resume.
channel_public_base now defaults to the documented production origin like
the commit-build path, so a local command names its page without a
hand-set CLOUDFLARE_R2_PUBLIC_URL.
Also drops a stale fork-isolation assertion left behind by the
fork-conditional dispatch removal.
d786c08e37