feat: add Truth Bear fact-verification action provider

[CHANGCHINFU]

Summary

• Add truthbearActionProvider — verifies facts against 180+ official government and institutional data sources (USGS, NOAA, SEC EDGAR, EPA, FRED)
• Free /trust/preview endpoint: no API key, no wallet, no signup required
• Each response includes signal name, value, source URL, SHA-256 record_hash (Bitcoin-anchored via OpenTimestamps), and freshness timestamp
• Network-agnostic (pure API, no on-chain interaction for free preview)

Files

File	Purpose
truthbear/schemas.ts	Zod input schema (query string)
truthbear/truthbearActionProvider.ts	Action provider with truthbear_verify action
truthbear/truthbearActionProvider.test.ts	6 unit tests (success, error, network error, empty, partial, supportsNetwork)
truthbear/index.ts	Re-export
index.ts	Added truthbear export (alphabetical order)

Design

Follows the defillama pattern — wallet-free ActionProvider with supportsNetwork() → true. Single action truthbear_verify calls GET /trust/preview?q={query} and formats the response as human-readable lines.

Also available as:

• MCP server: mcp-gauge-x402 on npm
• LangChain tools: langchain-truthbear on PyPI
• CrewAI tool: crewAIInc/crewAI-tools#7166

Test plan

• Unit tests cover success, HTTP error, network error, empty response, partial response, and supportsNetwork
• Manual test with AgentKit + Claude Desktop

🤖 Generated with Claude Code

[cb-heimdall]

🟡 Heimdall Review Status

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