fix: verify OpenClaw and refresh cheap-tier pricing

[ramioca]

What changed

• Mark OpenClaw 2026.8.2 as verified with the published npx package.
• Add the tested OpenClaw install + doctor --probe flow with a hard $2 budget cap.
• Document the WebChat → Codex spend-elicitation behavior so new users do not accidentally make every paid call decline.
• Refresh deepseek/deepseek-v4-pro from $0.435/$0.87 to the live $1.32/$3.96 per-million-token quote.
• Update the 100k-character live-charge regression fixture from $0.021977 to $0.064790.

Why

The OpenClaw row still described an unverified local-build setup even though the published package now works end-to-end: OpenClaw projects all 20 tools and completes free and paid calls.

The same verification run found a budget-safety regression. mode:"cheap" reserved $0.026310 for the verifier's 100k-character prompt while the Base gateway quoted $0.064790. A call could therefore pass BLOCKRUN_BUDGET_LIMIT while settling above it.

Verification

• openclaw mcp doctor blockrun --probe --json — clean, no issues
• OpenClaw live smoke test — wallet, model catalogue, free chat, DEX, price discovery, RPC, DefiLlama, Surf, Exa, phone inventory, speech voices, RealFace inventory, and Polymarket reads
• npm run typecheck
• npm test — 431/431 passing
• npm run build
• npm run verify:prices — 0 under-reserving routes (previously 1)

The live probe also reproduced upstream 502s on blockrun_price quotes and blockrun_markets; those are not changed here because the MCP client is forwarding the requests successfully.