[Editor] Add autosave and file persistence system

[Atharv777]

Summary

Automatically save file changes and ensure project state is consistently persisted.

Why this matters

Manual saving leads to lost work. Autosave ensures:

• data safety
• smoother UX
• fewer accidental losses

Scope

• Add autosave trigger (interval or on change)
• Persist file contents to backend
• Add visual indicator for save status
• Handle save conflicts or failures
• Optimize to avoid excessive API calls

Acceptance Criteria

• Changes are saved automatically
• Save status is visible in UI
• No data loss on refresh
• Backend correctly stores file state
• Performance remains stable

Files Involved

• pages/app/index.jsx
• components/* (editor UI)
• server/project_routes.py
• server/db_utils.py

Difficulty

Medium

Labels: frontend editor backend