[buqizixv]

Problem

Confirming the Daycast family-weather reminder opens Rinx's native send-prompt flow, then Rinx stops with a draw panic. The shell log reports the hosted Rinx module panicking in draw with called Option::unwrap() on a None value; this occurs before a provider reply is involved.

A hosted Splash module's Root belongs to its isolated VM. Makepad's current set_ui_root path stores that VM-owned WidgetRef in the process-global widget tree, so a hosted app can replace the host's root and leave the shell with an invalid widget handle.

Change

• Keep main Splash root registration unchanged.
• For non-main Splash VMs, inject the root handle into that isolate instead of replacing the process-global root.
• Record the Makepad fix in the pinned runtime overlay and add a regression test using the real Rinx module through ShowPrompt, HidePrompt, and ShowPrompt.

Validation

• cargo test --locked --offline --release -p octosense-shell --lib --no-default-features --features app-rinx rinx_reminder_confirmation_does_not_stop_the_module -- --nocapture passed (1 test).
• git diff --check passed.
• python tools/setup.py --check --cargo could not run because the local Makepad checkout has local changes; the exact overlay is recorded in runtime-patches.lock.json for CI to verify.

Fixes #536