TS_Notification suite + Readme suites

[humanagent]

Reorganize test suites and implement new TS_Notifications test suite for validating XMTP notification functionality

• Adds new TS_Notifications test suite in TS_Notifications.test.ts that sends 10 sequential messages from random senders within 30 seconds
• Moves existing test suites into dedicated directories with accompanying README documentation
• Removes debug logging from clients.test.ts and main.ts
• Deletes unused test data file convos-inboxes.json
• Updates test suite documentation structure with new README files for each test suite

📍Where to Start

Start with the new notification test implementation in TS_Notifications.test.ts, which contains the core test logic for sending sequential messages from random senders.

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Macroscope summarized 938354a.