Fix #7: Auto-solve hCaptcha with integrated solver & retry logic

[chfr19820610-cell]

Summary

Fixes #7 - 500 Server Error caused by hCaptcha challenges on Udio API.

This PR adds a fully integrated hCaptcha auto-solving system that actually works end-to-end, unlike the existing open PRs (#36-40) which either don't integrate the solver or have incomplete implementations.

Changes

New: udio_wrapper/hcaptcha_solver.py

• HCaptchaSolver class with full hCaptcha solving pipeline
• Capsolver support (CAPSOLVER_API_KEY env var) - most reliable for hCaptcha
• 2captcha support (CAPTCHA_API_KEY env var) - budget-friendly alternative
• Manual token input fallback when no API key is configured
• Dynamic sitekey extraction from Udio homepage (with fallback)
• Token caching (110s TTL) to minimize API calls

Modified: udio_wrapper/__init__.py

• make_request(): Automatic h-captcha-response header injection for POST requests
• Retry logic: Detects 403/500/503 errors, clears cached token, retries with fresh solve
• Exponential backoff on network/HTTP failures
• New constructor params: captcha_api_key and captcha_service for simple setup
• Backward compatible: Works without captcha key (falls back to manual input)

Usage

# With Capsolver (recommended)
from udio_wrapper import UdioWrapper
wrapper = UdioWrapper(auth_token="your_token", captcha_api_key="caps-...")

# With 2captcha
wrapper = UdioWrapper(auth_token="your_token", captcha_api_key="2cap-...", captcha_service="2captcha")

# With env var
export CAPSOLVER_API_KEY=caps-...
wrapper = UdioWrapper(auth_token="your_token")

# Without API key (manual input)
wrapper = UdioWrapper(auth_token="your_token")  # will prompt for token
result = wrapper.create_song("a happy jazz song")

Why this PR should be merged

1. Actually integrated - Unlike Fix #7: 500 Server Error - Auto Solve hcapcha #40 which adds a standalone solver file that's never imported
2. Functioning retry - Detects failures, refreshes token, retries automatically
3. Multi-service - Supports both Capsolver and 2captcha
4. Fallback chain - Capsolver → 2captcha → manual input
5. Clean code - Single class, clear responsibilities, no global state
6. Documented - Clear error messages guide users through setup

/claim #7

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Closes #7

[opirebot]

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