feat: implement real-time room management and sidebar navigation with voice context integration

[aninda8680]

Summary

Resolves the TypeScript compilation failures occurring during the npm run build process. The fixes address incorrect property access on the User object within the dashboard sidebar and solve type inference issues with Mongoose queries in the backend server script.

Related issue

Fixes #66

Changes

• Fixed Type error: Property 'color' does not exist on type 'User' in DashboardSidebar.tsx by correctly accessing the nested property via user.avatarConfig?.color (applied to both callu-web and callu-desktop).
• Fixed error TS2349: This expression is not callable in server.ts by adding a type assertion (Room as any) to Room.findById queries to bypass the union type inference conflict caused by mongoose.models.

Testing

• Ran npm run build locally in the callu-web directory and verified that both the Next.js optimization and the server.ts TypeScript compilation pass with exit code 0.
• Verified that joining a private room through the dashboard still correctly reads the user's avatar color or falls back to the default hex code.

Checklist

• Title follows the repository PR format
• The issue is linked with Fixes #66
• Testing notes are included

[github-actions]

✅ PR Validation Passed

Your PR title and description meet all requirements:

• Title follows conventional format
• All required sections are present
• Issue is properly linked (issues while creating private/public room #66)