Feature websockets

[ShashwatXD]

PR Description

• Added full WebSocket flow: connect, send/receive messages, disconnect
• Improved connection/error UX (clean error messages, proper failed/connected states)
• WebSocket sessions and messages are now saved to History after disconnect
• Added basic terminal logs for WebSocket lifecycle events
• Ensured existing functionalities continue to work as expected.

Related Issues

• Closes Feature request: Websocket Support #15

Checklist

• I have gone through the contributing guide
• I have updated my branch and synced it with project main branch before making this PR
• I am using the latest Flutter stable branch (run flutter upgrade and verify)
• I have run the tests (flutter test) and all tests are passing

Added/updated tests?

We encourage you to add relevant test cases.

• Yes
• No, and this is why: Manually verified. WebSocket streams and persistence require complex mocking, so automated tests are not added yet. Only model verification has been added for now.

OS on which you have developed and tested the feature?

• Windows
• macOS
• Linux

[ShashwatXD]

@animator Please review