#12707: docs: Add BlockRun provider (smart LLM routing + pay-per-request)

## Summary Adds BlockRun as a provider option for OpenClaw users. **What BlockRun offers:** - **Smart routing**: 15-dimension weighted scoring routes each request to the cheapest capable model (<1ms, 100% local) - **Pay-per-request**: No API keys needed — agents pay directly per request - **30+ models**: OpenAI, Anthropic, Google, DeepSeek, xAI, Moonshot through one integration - **78% cost savings**: Simple tasks go to cheap models, complex tasks to capable ones **Why this matters for OpenClaw users:** 1. **Global access** — Developers without first-world credit cards can access OpenClaw. No Stripe, no API key approvals, just fund a wallet and go. 2. **Cost optimization** — Addresses Issue #6445 and similar pain points. Smart routing sends "what is 2+2?" to Gemini Flash ($0.15/M) instead of Opus ($75/M). 3. **Agent autonomy** — Agents can generate their own wallets and pay for their own API calls without human intervention. ## Changes - `docs/providers/blockrun.md` - New provider documentation - `docs/providers/index.md` - Added BlockRun to provider list ## Related - Discussion: https://github.com/openclaw/openclaw/discussions/12465 - GitHub: https://github.com/BlockRunAI/ClawRouter ## Checklist - [x] Follows existing provider doc format - [x] Uses npm install (not curl|bash) - [x] Includes setup instructions - [x] Includes model identifiers - [x] Links to official docs - [x] Added to provider index <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> Adds a new provider documentation page for BlockRun and links it from the model provider index so users can configure `blockrun/*` model identifiers via the ClawRouter plugin. <h3>Confidence Score: 4/5</h3> - This PR is safe to merge once the minor docs consistency issue is addressed. - Changes are limited to adding a new provider doc page and a link in the providers index; no runtime code is touched. Only issue found is an inconsistent external npm URL format compared to existing provider docs. - docs/providers/blockrun.md <!-- greptile_other_comments_section --> <!-- /greptile_comment -->