feat: Add SessionPlayer as default tab in browser test editor

[allansson]

Description

Adds a Replay tab next to Script in the browser test editor’s main panel. The replay view uses the existing SessionPlayer from src/views/Validator/Browser/SessionPlayer (imported via @src/... so incoming merges can align with that path). Replay is the first tab and the default (defaultValue="replay").

Introduces a @src/* TypeScript path alias (same resolution as @/*) so the @src/views/... import resolves in the IDE and Vite.

SessionPlayer receives highlightedSelector={null} for now (no locator highlight wiring in the editor yet).

How to Test

1. Open a browser test in the editor (#/editor/<name>.k6b).
2. Confirm the main left panel shows Replay first and opens on that tab by default.
3. Start a run from the controls; confirm replay UI behaves as in the validator (timeline, viewport).
4. Switch to Script and confirm the generated TypeScript preview still appears.

Checklist

• I have performed a self-review of my code.
• I have added tests for my changes.
• I have commented on my code, particularly in hard-to-understand areas.