Carry the per-run duplex bridge kill switch from the instance setting to
every caller of startAdapterExecutionTargetPaperclipBridge. The host reads
readSandboxDuplexBridgeInput() and stamps enableSandboxDuplexBridge on the
sandbox target, on the same seam as effectiveCapabilities. The value stays on
the host and never enters the sandbox environment.
The stamp fails closed. An absent runtime, an absent read method, a read
error, or any value other than true keeps the file bridge. The adapter-side
spec parse reads the boolean and treats an absent or non-boolean field as no
grant. The acpx engine and the six local adapter callers pass the parsed value
into the bridge, so the two-gate selection is now reachable.
Co-authored-by: Paperclip <noreply@paperclip.ing>
