feat: centralize configuration and secure firebase handling

[bhoomiiee]

Problem

• Previously, Firebase configuration values were either hardcoded or implicitly handled across modules. This creates:
• Security risks (exposed API keys in frontend)
• Tight coupling between frontend & config values
• Difficult scalability for future integrations
• Risk of configuration drift

What This PR Implements
-Centralized Backend Configuration
Added /api/firebase-config endpoint in app.py
Firebase configuration is now read securely from environment variables
No sensitive credentials are stored in frontend files

• Secure Environment-Based Setup
  The following variables are now expected:
  FIREBASE_API_KEY
  FIREBASE_AUTH_DOMAIN
  FIREBASE_PROJECT_ID
  FIREBASE_STORAGE_BUCKET
  FIREBASE_MESSAGING_SENDER_ID
  FIREBASE_APP_ID
  FIREBASE_MEASUREMENT_ID

• Graceful Degradation
  If Firebase variables are not configured, API returns null values
  Frontend logs a warning:
  "Firebase not configured on server."
  Application does not crash

-Frontend Refactor
Removed hardcoded Firebase config from JS
Added dynamic fetch:
fetch('/api/firebase-config')
Firebase now initializes only after config is retrieved

-Testing Performed
Verified /api/firebase-config returns 200
Confirmed null-safe behavior when environment variables are missing
Confirmed no Firebase credentials are exposed in frontend source
Checked Network tab for successful fetch
Verified console warnings are expected and handled

-What Is NOT Included (Future Scope)
Strict runtime schema validation across all modules
Full migration of all modules to shared domain contracts
Production deployment configuration
Actual Firebase production keys (intentionally excluded)

• Impact
  Improves security posture
  Prepares system for scaling
  Makes configuration environment-agnostic
  Enables safer ML/API integrations in future

[vercel]

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[github-actions]

Thanks for creating a PR for your Issue! ☺️

We'll review it as soon as possible.
In the meantime, please double-check the file changes and ensure that all commits are accurate.

If there are any unresolved review comments, feel free to resolve them. 🙌🏼

[omroy07]

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