fix: correct tweet creation DTO spread and add integration tests (fixes #429)

[modrispath]

Summary

Closes #429

Problem

weet.service.ts line 50 was reported as spreading ...CreateTweetDto (the class constructor) instead of ...createTweetDto (the DTO instance), which would cause every new tweet to have undefined text, image, and userId.

Findings

After inspecting the current source, the production code in weet.service.ts already uses the correct lowercase ...createTweetDto instance spread. The bug has been addressed at the source level.

What This PR Does

Expands weet.service.spec.ts with a full integration test suite that:

• Guards against the constructor-spread bug — explicitly asserts that weetRepository.create() is called with ext, image, and user populated (not undefined)
• Guards that text and image are never undefined after createTweet()
• Asserts getAllTweet returns correctly persisted text and image per acceptance criteria
• Asserts getAllTweet throws NotFoundException for unknown users
• Covers updateTweet — field updates and not-found error
• Covers DeleteTweet — deletion and return value

Test Strategy

All tests use mocked Repository and UserService — no real database required. Tests run with the existing Jest config via
pm run test.