[Page] Fix: Align prototype frontend with spx-gui

[qingqing-ux]

Issue

• N/A

Background

Sync the standalone prototype frontend with the current spx-gui preview surfaces so product review can run offline without server data.

Changes

• Aligned tutorials banner, community navbar project menu, and search empty results layout with spx-gui.
• Completed editor prototype interactions for project menu, save status, code categories, asset tabs, sprite/stage controls, map mode, and copilot dragging.
• Kept prototype data and actions local with deterministic mock behavior.

Scope

• Prototype community pages
• Prototype tutorials page
• Prototype search page
• Prototype editor page
• Shared prototype assets and local UI helpers

Design System Impact

• Yes
• No