[Refactor] Reuse shared webview render helpers in chat tests

[zoomote]

Created by Roomote. View the task or mention @roomote for follow-up asks.

Related GitHub Issue

N/A: Phase 3 webview test-utils refactor batch.

Description

Reuses the shared renderWithExtensionState helper across four focused ChatRow specs instead of assembling extension-state and React Query providers in each file. Scenario-specific component mocks, message fixtures, callbacks, and assertions remain local and unchanged.

This is a test-only refactor with no intended runtime or user-facing behavior change.

Test Procedure

• pnpm exec vitest run src/components/chat/__tests__/ChatRow.run-slash-command.spec.tsx src/components/chat/__tests__/ChatRow.rate-limit-wait.spec.tsx src/components/chat/__tests__/ChatRow.diff-actions.spec.tsx src/components/chat/__tests__/ChatRow.command-denied.spec.tsx from webview-ui (4 files, 16 tests passed)
• pnpm test (444 files passed, 4 skipped; 7,351 tests passed, 39 skipped)
• pnpm lint
• pnpm check-types

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes (if applicable).
• Visual Snapshot (UI changes only): Not applicable; this is a test-only refactor with no rendered UI change.
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Visual Snapshots

Not applicable; no product UI changed.

Videos (interaction / animation only)

Not applicable; no product interaction changed.

Documentation Updates

• No documentation updates are required.
• Yes, documentation updates are required.

Additional Notes

No changesets were added. Author self-review found no behavior or scope regressions.

Get in Touch

Mention @roomote on this PR for follow-up requests.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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