Add no-registration upload providers

[j0rd1s3rr4n0]

Summary

Add more upload providers that work without account registration or API keys.

Providers

• 0x0.st
• MoonPush
• Temp.sh
• tmpfile.link
• blipbin
• EasySend
• dropfile.dev
• cupload.io
• qurl.sh

Acceptance criteria

• Providers are listed by the unified registry.
• CLI/GUI/TUI can use them through the existing provider core.
• Plain-text, JSON, and PUT-style upload responses are normalized into UploadResult.
• Unit tests cover provider normalization without real network calls.
• README documents which providers do not require registration.