Add Gonka Broker (Inference providers)

[iamoeco]

Adds Gonka Broker — an OpenAI-compatible gateway to open-source models
running on the decentralized Gonka GPU network.

Meets the "What counts" criteria:

• Permanent free tier: 1M+ tokens/month across all models, resets monthly (recurring tier, not trial credits). Documented at https://gonkabroker.com/free-llm-api/ and https://docs.gonkabroker.com/guides/billing-and-deposits/#free-tier.
• No credit card required to sign up.
• Real REST API for LLM inference (OpenAI-compatible /v1/chat/completions and /v1/embeddings).

The model lineup rotates with network governance; the live list is available unauthenticated at https://proxy.gonkabroker.com/v1/models.

Included per repo structure: data.json entry, README regenerated with scripts/generate-readme.js (no manual README edits), skill reference section in free-llm-apis/references/inference-providers.md, and the provider list in free-llm-apis/SKILL.md.

[SebConejo]

Thanks, this is a well-formed PR. I add entries only after verifying the free tier myself with a real request, so I will evaluate Gonka Broker independently and come back to this PR with the outcome. If it checks out it ships with credit to you.