Fix: Mime issue

[Aravinda-HWK]

📌 Description

This PR is to resolve the issue of loading an email with an attachment and text.

• Closes [TASK] Implement MIME parser and reconstructure based on RFC #128

---

🔍 Changes Made

• Fix the loading the attachments in Apple Mail and Gmail clients.
• Handle nested multiparts

✅ Checklist (Email System)

• Core IMAP commands tested (LOGIN, CAPABILITY, LIST, SELECT, FETCH, LOGOUT).
• Authentication is tested.
• Docker build & run validated.
• Configuration loading verified for default and custom paths.
• Persistent storage with Docker volume verified.
• Error handling and logging verified
• Documentation updated (README, config samples).

---

🧪 Testing Instructions

To test the server, use the instructions in the README in the test directory.

---

📷 Screenshots / Logs (if applicable)

---

⚠️ Notes for Reviewers