docs(security): remove duplicated content in SECURITY.md (JhaSourav07#281)

## Description

Fixes JhaSourav07#280 

Removed the accidental duplication of the security policy where lines
1-65 were repeated verbatim at the end of the file.

## Pillar

- [ ] 🎨 Pillar 1 — New Theme Design
- [ ] 📐 Pillar 2 — Geometric SVG Improvement
- [ ] 🕐 Pillar 3 — Timezone Logic Optimization
- [x] 🛠️ Other (Bug fix, refactoring, docs)

## Visual Preview

## Checklist before requesting a review:

- [x] I have read the `CONTRIBUTING.md` file.
- [x] I have tested these changes locally
(`localhost:3000/api/streak?user=YOUR_USERNAME`).
- [x] I have run `npm run format` and `npm run lint` locally and
resolved all errors (CI will fail otherwise).
- [x] My commits follow the Conventional Commits format (e.g.,
`feat(themes): ...`, `fix(calculate): ...`).
- [x] I have updated `README.md` if I added a new theme or URL
parameter.
- [x] I have started the repo.
- [x] I have made sure that i have only one commit to merge in this PR.
- [x] The SVG output matches the CommitPulse "premium quality" aesthetic
standard (no raw elements, smooth animations, correct fonts).
- [x] (Recommended) I joined the CommitPulse Discord community for
contributor discussions, mentorship, and faster PR support.

Author: JhaSourav07

SECURITY.md

@@ -62,68 +62,3 @@ We appreciate responsible disclosure and will:
 ## 🙏 Acknowledgements
 
 Thanks to all contributors who help keep CommitPulse secure.
-
-# 🔐 Security Policy
-
-## 📢 Reporting a Vulnerability
-
-We take the security of CommitPulse seriously. If you discover a vulnerability, please report it responsibly.
-
-- Please contact maintainers via GitHub (preferred)
-
-Please include:
-
-- Description of the vulnerability
-- Steps to reproduce
-- Potential impact
-- Suggested fix (if possible)
-
-⚠️ Please do NOT create public issues for security vulnerabilities.
-
----
-
-## 🛡️ Supported Versions
-
-We aim to support the latest version of CommitPulse.
-
-| Version | Supported |
-| ------- | --------- |
-| Latest  | ✅ Yes    |
-| Older   | ❌ No     |
-
----
-
-## 🔒 Security Best Practices
-
-To keep your usage secure:
-
-- Always install from trusted sources
-- Avoid running the tool on untrusted repositories
-- Keep your dependencies updated
-- Do not expose sensitive tokens or credentials
-
----
-
-## 🔐 Data & Privacy
-
-CommitPulse is designed with privacy in mind:
-
-- No source code is uploaded or stored
-- Only Git metadata is analyzed
-- Local analysis mode ensures full control over your data
-
----
-
-## ⚙️ Responsible Disclosure
-
-We appreciate responsible disclosure and will:
-
-- Respond within 48–72 hours
-- Investigate and fix issues promptly
-- Credit contributors (if desired)
-
----
-
-## 🙏 Acknowledgements
-
-Thanks to all contributors who help keep CommitPulse secure.