## **Description**

Fixes a shared Popover listener leak that retained old route trees
during send/settings route churn.

Popover registered document `keydown` and `click` listeners with capture
enabled, but removed them without matching capture options. Since
`removeEventListener` matches on event type, callback, and capture flag,
cleanup failed and leaked document listeners retained their React
closure scope.

This PR keeps the change scoped to
`ui/components/component-library/popover/popover.tsx` by:

- defining one shared capture listener options object
- adding document listeners only while the Popover is open and the
matching callback exists
- removing those listeners with the same callback and capture options
- adding a regression test that verifies unmount cleanup uses the same
listener and options captured from `addEventListener`

## **Changelog**

CHANGELOG entry: null

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## **Related issues**

Fixes:
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## **Manual testing steps**

1. Build the test extension:
   ```bash
   source ~/.nvm/nvm.sh && nvm use
   yarn build:test:webpack
   ```
2. The `yarn llm:memory` profiler is available on the separate [profiler
PR](MetaMask#42733). With
that tooling available and this branch's `dist/chrome` build, run:
   ```bash
yarn llm:memory -- --iterations 50 --flow send-open-back --sample final
--probe cdp --wait-after-flow 500 --extension-path dist/chrome
yarn llm:memory -- --iterations 100 --flow settings-route --sample final
--probe cdp --wait-after-flow 500 --extension-path dist/chrome
   ```
3. Expected post-fix profile from the prior investigation with the [Snow
WeakMap patch](LavaMoat/snow#170) still applied:

   | Flow | Before | After |
   |---|---:|---:|
   | settings-route 50x | +118.91 MiB | +2.22 MiB rerun, +37 listeners |
   | settings-route 100x | n/a | -0.34 MiB, +34 listeners |
   | settings-route 50x paired heap snapshots | n/a | -5.84 MiB |
   | send-open-back 50x | +111.66 MiB | +0.05 MiB, +307 listeners |

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## **Screenshots/Recordings**

If applicable, add screenshots and/or recordings to visualize the before
and after of your change.

### **Before**

[screenshots/recordings]

### **After**

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## **Validation**

- `source ~/.nvm/nvm.sh && nvm use && yarn test:unit
ui/components/component-library/popover/popover.test.tsx`
- `source ~/.nvm/nvm.sh && nvm use && yarn lint:changed:fix`
- `source ~/.nvm/nvm.sh && nvm use && yarn webpack:tsc`
- `source ~/.nvm/nvm.sh && nvm use && yarn build:test:webpack`

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I've included tests if applicable
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk: scoped to Popover’s document event listener lifecycle and
adds a regression test; main risk is behavior change in when listeners
are attached (only when open and handlers provided).
> 
> **Overview**
> Fixes a Popover document-listener leak by **reusing a shared capture
options object** and ensuring `removeEventListener` is called with the
*same* callback and capture options used for `addEventListener`.
> 
> Listeners for `keydown` (Esc) and `click` (outside) are now only
attached when the popover is open and the corresponding handler prop is
provided, and a new unit test asserts the add/remove signatures match on
unmount to prevent regressions.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
0ccfb58. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->