Feature Request: Support Claude Code (CC) subscription authentication

[heiheimaoya]

Suggestion

Currently, moltworker requires an Anthropic API key (or AI Gateway) for Claude access. It would be great to also support authentication via Claude Code subscription (Claude Pro / Max plans), which uses OAuth-based login instead of API keys.

Why

• Many users already have Claude Pro/Max subscriptions but don't have separate API credits
• Claude Code subscription includes usage allowance that could be leveraged here
• Lowers the barrier to entry — no need to manage API keys separately
• OAuth flow is more user-friendly than manually setting secrets

Possible approach

Support the same OAuth authentication flow that Claude Code CLI uses (claude login), allowing users to authenticate with their Anthropic account subscription instead of an API key.

[vhscom]

Related pull: #52