[rdlabo]

Native CI has encountered two distinct failures: a popover deadline test that depends on simulator scheduling, and HTTP 504/timeouts downloading Swift binary dependencies or the Gradle distribution before tests start.

Inject the dismissal deadline scheduler internally into NativeUIOverlayHost. Production retains its four-second main-queue deadline. Tests explicitly fire scheduled work and verify the deadline, one cancellation, completion of overlapping callers, protection against late duplicate completion, and cancellation of the fallback after normal disappearance.

Resolve Swift dependencies and download the Gradle distribution in dedicated preparation steps. Swift resolution and both test invocations share a source-package directory. Only recognized transient download errors are retried, for at most three attempts; invalid dependencies and checksum/assertion errors fail immediately. Build and test commands are not wrapped in retries.

Validation:

• Two deadline tests passed 10 iterations each (20 executions) on an iPhone simulator.
• The regular Swift suite passed with the same three hosted-test exclusions as CI (73 plugin tests and 4 shared-core tests).
• Seven retry-policy tests verify success, recovery, bounded attempts, and immediate failure for non-transient errors.
• Both actual Swift dependency-resolution commands passed locally using the shared directory; shell syntax and git diff checks passed.

The CI run on this updated head remains the acceptance check. This does not claim to eliminate external service outages or address the separate npm publish error.