fix(socket): improve connection reliability and surface errors

[ayushhh101]

Description

• Improve Socket.IO reliability and visibility of errors in development.
• Use connect event (instead of connection) in client.
• Add reconnection strategy and toasts for connect_error, reconnect_attempt, reconnect, reconnect_failed.
• Subscribe to server notification and command_ack events.
• Memoize notification actions (addNotification, removeNotification, clearNotifications) to stabilize effect dependencies.
• Allow Vite dev origin (http://localhost:5173) in mock server CORS.

Affected files:

• src/context/SocketContext.jsx
• src/context/NotificationContext.jsx
• server/mock-socket-server.js

Semver Changes

• Patch (bug fix, no new features)
• Minor (new features, no breaking changes)
• Major (breaking changes)

Issues

List any issues that this pull request closes.

Checklist

• I have read the Contributing Guidelines.

[ayushhh101]

Hi @rajshekharbind , the label checker is blocking the PR. Could you please add:
Type: Easy
Semver: Patch
PR:Accept
Thanks!