File attachment support

• Enable image/document/voice upload via Telegram
• Validate file size/type before storing
• Link uploaded files to the corresponding task

📋 Acceptance Criteria

✅ What to consider:

• Users should be able to upload various types of files (images, documents, voice messages) via Telegram.
• Uploaded files must be validated for both size and type before being stored.
• Each uploaded file must be correctly linked to the corresponding task for reference and tracking.

✅ Acceptance Criteria (AC):

• GIVEN a user sends an image, document, or voice file via Telegram

• WHEN the file is received by the bot

• THEN it is accepted and processed if the file type is supported

• GIVEN a file is uploaded

• WHEN it exceeds the allowed size or is of an unsupported type

• THEN the upload is rejected and the user receives an appropriate error message

• GIVEN a valid file is uploaded and accepted

• WHEN it is stored

• THEN it is linked to the relevant task and can be accessed from the task details

✅ Please check the Definition of Done before moving this issue to Close.