Raise requestsPerMinute from 10 to 20 and add requestsPerDay (1000) to
match OpenRouter free-tier limits. The generation queue now tracks daily
usage and resets at midnight, resolving requests with null once the cap
is hit. Both GenerationQueue and LlmService expose isDailyLimitReached().
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Reads API key and model from environment variables. LLM is disabled by
default and auto-enables when OPENROUTER_API_KEY is set.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>