chore: move scroll restoration and focus reset out of client.js

[Nic-Polumeyv]

Scroll restoration and focus reset live in client.js but read none of its state. This moves them, unchanged, into their own module, the shape snapshots.js took in #16685.

Summary by CodeRabbit

• Improvements
  • Improved focus restoration after navigation, including autofocus targets, hash targets, and fallback to the page body.
  • Improved scroll-position restoration when navigating backward or forward.
  • Hash navigation now more reliably identifies and scrolls to the intended page element.
  • Preserved scroll and focus state during replacement navigation.
  • Prevented unwanted automatic scrolling when navigation explicitly manages scroll position.

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 01f7ffb:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/01f7ffb627052025412c596a1ca1ebb0cf40600c

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16980

[changeset-bot]

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Latest commit: 01f7ffb

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[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-kit-16980-svelte.vercel.app/

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 7d120c65-4c93-44a1-baef-62f13dfd18fb

📥 Commits

Reviewing files that changed from the base of the PR and between 2eed638 and 01f7ffb.

📒 Files selected for processing (6)

• packages/kit/src/runtime/client/client.js
• packages/kit/src/runtime/client/focus.js
• packages/kit/src/runtime/client/focus.spec.js
• packages/kit/src/runtime/client/scroll.js
• packages/kit/src/runtime/client/scroll.spec.js
• packages/kit/src/runtime/client/utils.js

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📝 Walkthrough

Walkthrough

Focus, hash lookup, and scroll management move from client.js into dedicated runtime modules. Client navigation imports the new helpers. Vitest coverage validates focus restoration, hash navigation, scroll restoration, and one-navigation scroll suppression.

Changes

Client navigation focus and scroll handling

Layer / File(s)	Summary
Focus restoration and hash lookup packages/kit/src/runtime/client/focus.js, packages/kit/src/runtime/client/utils.js, packages/kit/src/runtime/client/focus.spec.js	Focus restoration now handles autofocus elements, hash targets, body fallback, selection cleanup, and decoded fragment lookup. Tests cover body focus and hash scroll restoration.
Scroll restoration and suppression packages/kit/src/runtime/client/scroll.js, packages/kit/src/runtime/client/scroll.spec.js	Scroll handling restores saved coordinates, hash targets, or the top position. A suppression flag applies to one navigation and is consumed in all reset modes.
Navigation wiring packages/kit/src/runtime/client/client.js	client.js imports the helpers and uses them for navigation scroll control, popstate focus checks, and focus and hash handling.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Merge Risk: ⚪ Minimal · up to 01f7f

This PR reorganizes existing focus-reset and scroll-restoration behavior without changing its intended runtime behavior. The change is localized and merge-ready after normal checks, with no actionable merge-blocking risk remaining.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 76.92% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 13 functions across 6 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: moving scroll restoration and focus reset logic out of client.js.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch client-focus-module

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