[sean0407]

Summary

close modal
  schedule reset after 300 ms
reopen before reset
  cancel stale reset and preserve the active modal

Addresses Bug 2 from #567 only. Bug 1's component-history race is outside this change. Adds a focused Node regression test and runs it in CI.

Evidence

• Before: An isolated VM reproduced the stale close timer clearing activeComponent after a modal was reopened.
• After: npm run test:js — 2 tests passed.

Merge Danger

Door: Two-way

Blast Radius: Low

Only modal close cleanup changes; reopening cancels the pending reset.