168-30-22-6-4-2-vipul-patial

[vipulpatial82]

Summary (max 3 sentences)

Fixed server-side session invalidation on logout, blocked admin-to-admin task assignment, and restricted file uploads to safe types (Issues #6, #2, #4). Added a rich text editor for task descriptions and submission notes, an interactive onboarding wizard for new users, and a password visibility toggle on login/register (Issues #22, #168, #30). All changes tested locally with passing lint and build checks on both client and server.

Checklist

Required before opening this PR: Complete these checks locally to ensure the code is ready for review. PRs opened without these checks passing may be closed.

• I ran cd client && npm run lint && npm run build and cd server && npm run lint && npm run build locally
• All checks passed (lint, build)
• No errors or warnings remain

Note: This is a pre-PR checklist completed before submission. Additional checklists below are completed after the PR is opened.

Short Demo Video (required)

[Link to be added after recording]

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• I have read and followed the Contribution and Qualification Guidelines

Required Checklist

Task & Workflow

• Create a new Branch exactly matching your assigned name (e.g. 27-26-22-7-5-pranav-test)
• PR title is exactly your assigned branch name
• Latest target branch (master) was pulled immediately before opening this PR

Quality & Safety

• Change tested locally
• Full diff reviewed before submitting (no blind copy/paste)
• No secrets, keys, or personal data included

Closes #6, Closes #2, Closes #4, Closes #22, Closes #168, Closes #30