feat(backend): implement structured Winston logging and align test suite

[Aayuiiitmg]

Description

Implemented structured, secure logging using the Winston logging library and resolved test suite integration issues.

Key Changes:

• Configured a production-grade Winston logger supporting file rotation (5MB size, max 5 files), environment-based level mapping (warn in production, debug in development), and colorized console output in development.
• Refactored db.js, server.js, and aiController.js to eliminate direct, un-bracketed console.log and console.error calls, ensuring that sensitive internals and PII are protected in production.
• Refactored tests/lifecycle.test.js Step 4 to match the actual controller database query sequence by mocking the intermediate requestDataQuery lookup.
• Refactored tests/lifecycle.test.js Step 5 to query a valid UUIDv4 path to comply with route parameter validation middleware, and added proper mocking for the supabaseAdmin client.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Testing

How did you test this?

• Local development
• Manual testing
• Automated tests added

Both auth.test.js and lifecycle.test.js were run locally using Jest with simulated Redis and PostgreSQL environments, and all 10 tests passed successfully.

Checklist

• Code follows project style guidelines
• Self-reviewed the code
• Commented complex code
• Updated documentation
• No new warnings/errors
• Added tests (if applicable)

Screenshots (if UI changes)

No UI changes.

Related Issue

Fixes backend console data leak issue / structured logging request. Assigned under GSSoC'26.

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🏷️ Request to Maintainers: Difficulty Labeling (Intermediate / Advanced)

Dear Maintainers,

Could you please label this PR as Intermediate or Advanced?

Justification for Complexity Labeling:

1. Architectural Logger Unification: Designed and implemented a production-grade Winston logging configuration that automatically routes logs based on the environment (warn level in production for security, debug in development for trace visibility), standardizes JSON outputs, and sets up robust log file rotation (maxsize: 5MB, maxFiles: 5) to prevent disk exhaustion.
2. Security & PII Leakage Protection: Identified and systematically replaced direct, un-bracketed console.log statements in controllers, DB configs, and startup hooks that were leaking sensitive system internals, query blueprints, and user metadata.
3. Decoupling Mocks & Environment Isolation: Resolved race conditions in the test suite by encapsulating intensive database check-up queries (such as those scanning for PMA keys) strictly inside development checks. This prevents active Jest query queues from being hijacked during unit tests.
4. Advanced Jest Mock Alignment:
   • Step 4: Correctly lined up sequential, multi-stage mocked query resolutions for authentication, request-checking, and updating query steps, ensuring zero test context spillover or crashes.
   • Step 5: Handled strict middleware UUID validation by restructuring the test parameter and mocking the local supabaseAdmin client dynamically within Jest's module scope.

[AA1-34-Ganesh]

@Aayuiiitmg add the issue number.

[AA1-34-Ganesh]

@Aayuiiitmg, update the PR description with correct issue number present in the PR template. I will review and can assign another issue after this.