[FEATURE] Add Email Sender Reputation Scoring

[Aharshi3614]

Problem Statement

The system treats all senders equally, without considering sender reputation. A known malicious sender should trigger immediate spam classification, while trusted senders should have lower spam scores.

Proposed Solution

Implement a sender reputation system that tracks email addresses and domains:

Each sender starts with neutral score (50)

Positive feedback (marking as ham) increases score

Negative feedback (marking as spam) decreases score

Suspicious patterns (spoofing, mismatch) decrease score

[github-actions]

👋 Welcome back! Thanks for your continued contribution. Your issue/PR is received and waiting for maintainer review.

[github-actions]

The proposal suggests implementing an email sender reputation scoring system that assigns and adjusts reputation scores to email senders based on user feedback and suspicious behaviors. Trusted senders would receive lower spam scores, while known or suspected malicious senders would be flagged to improve spam detection.