fix: find app iframe by selector in chrome-remote-debugging hover task

[mschile]

Problem

In examples/fundamentals__chrome-remote-debugging, the activateHoverPseudo CDP task assumed the application-under-test was the first iframe in the flattened document:

const filtered = allRootNodes.nodes.filter(isIframe)
// The first IFrame is our App
const root = filtered[0].contentDocument

Cypress PR #34242 (reporter-in-iframe) renders the Cypress reporter/command-log into its own same-origin #reporter-frame iframe, which sorts before the AUT iframe (#unified-runner) in document order. That makes filtered[0] the reporter frame, so DOM.querySelector finds nothing, nodeId is undefined, and CSS.forcePseudoState throws Error: Could not find node with given id.

This currently fails the test-binary-against-recipes-chrome CI job on that Cypress PR (spec spec.cy.js, test "Hover pseudo element is active").

Fix

Search each same-origin iframe for the target selector rather than assuming a fixed position. This is robust to the reporter iframe, the app iframe, and any nesting/ordering.

Verification

Ran the recipe locally against Cypress 15.17.0 — all 6 tests pass, including "Hover pseudo element is active":

✓ Printable div is not visible normally
✓ Printable div is visible with 'print' media query
✓ Hover pseudo element is inactive normally
✓ Hover pseudo element is active
✓ check visibility of div
✓ div should be visible again before print media query is activated
6 passing

The change is backward-compatible with the current released runner (single AUT iframe) and forward-compatible with the reporter-in-iframe layout.

🤖 Generated with Claude Code

[cypress]

cypress-example-recipes    Run #132000

Run Properties:   Passed #132000  •  cabd809dca: fix: find app iframe by selector in chrome-remote-debugging hover task

Project	cypress-example-recipes
Branch Review	mschile/fix-hover-pseudo-reporter-iframe
Run status	Passed #132000
Run duration	12m 18s
Commit	cabd809dca: fix: find app iframe by selector in chrome-remote-debugging hover task
Committer	Matthew Schile
View all properties for this run ↗︎

---

Test results
Failures	0
Flaky	3
Pending	36
Skipped	0
Passing	634
View all changes introduced in this branch ↗︎

UI Coverage  15.53%
Untested elements	99
Tested elements	52

Accessibility  71.21%
Failed rules	7 critical   10 serious   4 moderate   1 minor
Failed elements	549