[tooltip] Close when active trigger unmounts

[michaldudak]

Summary

• Clear stale active-trigger state when the active trigger unregisters while the tooltip is open.
• Close the tooltip instead of implicitly re-anchoring it to another trigger.
• Cover contained and detached trigger removal.

Bug

When the active trigger unmounts, unregistering removes the DOM node from the trigger map but leaves the active trigger id/element in store state. Conditional or virtualized triggers can then leave the tooltip open against stale anchor state instead of closing.

Reproduction

• Before: https://codesandbox.io/s/v8rgxd?file=/src/App.tsx
• After: https://codesandbox.io/s/n87sc5?file=/src/App.tsx

Test plan

• pnpm test:jsdom popupStoreUtils --no-watch
• pnpm test:chromium TooltipRoot.detached-triggers --no-watch

[pkg-pr-new]

• base-ui-tanstack-start

• vite-css-base-ui-example

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/react@4886
  

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/utils@4886
  

commit: 1343bd5

[code-infra-dashboard]

Bundle size

Bundle	Parsed size	Gzip size
@base-ui/react	🔺+503B(+0.11%)	🔺+122B(+0.08%)

Details of bundle changes

Performance

Total duration: 1,640.79 ms +249.14 ms^(+17.9%) | Renders: 50 ⁽⁺⁰⁾ | Paint: 2,473.95 ms +344.89 ms^(+16.2%)

Test	Duration	Renders
Slider mount (300 instances)	266.26 ms 🔺+88.16 ms(+49.5%)	3 (+0)
Checkbox mount (500 instances)	104.38 ms 🔺+36.77 ms(+54.4%)	1 (+0)
Dialog mount (300 instances)	84.39 ms 🔺+25.30 ms(+42.8%)	1 (+0)
Tooltip mount (300 contained roots)	85.53 ms 🔺+23.34 ms(+37.5%)	1 (+0)

8 tests within noise — details

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