feat: add AssetFare read-only cross-chain quote provider

[odaiin]

What changed\n\nAdds an assetfare ActionProvider with two read-only actions:\n\n- assetfare_get_capabilities reads the live six-chain, 76-route surface and current availability.\n- assetfare_get_quote requests one fresh non-custodial bridge or cross-chain swap quote, including total token-path cost, expected and minimum receive, ETA, TTL, ordered provider path, exact 1bp step, and quote-bound continuation_v3.\n\nThe provider supports the current Polygon and Optimism native-USDC source-only directions and rejects those chains as destinations. It treats AssetFare as one unranked candidate and directs agents to compare fresh executable routes.\n\n## Security boundary\n\n- no private keys or seed phrases\n- no wallet authentication\n- no action preparation\n- no signing or submission\n- no swap, bridge, funding, or order creation\n- rejects secret, signed, unsafe continuation, route-summary, intent, amount, Across-classification, and payload-hash mutations\n- preserves the server_signing=false and server_submission=false boundary\n\n## Verification\n\n- package-local Jest: 19 tests passed\n- package-local TypeScript check passed\n- package-local ESLint passed\n- actual Python Core 2.4.1 fixture reproduces the typed-canonical-v1 hash after JavaScript unsafe-integer parsing\n- number/string, negative zero, unsafe integral number, and lone-surrogate hostile cases pass\n- git diff check passed\n- the commit is GitHub-signed and verified\n\nThe public API and source are documented in the included provider README.\n\nCloses #1500\n\n## Checklist\n\n- [x] Added documentation to all relevant README.md files\n- [x] Added a changelog entry

Caller-owned continuation update

The provider remains read-only and still returns only a sanitized unranked continuation descriptor. It now also returns a structured executable/args handoff pinned to assetfare-mcp@1.3.0: first obtain a new exact validated mode-0600 quote file, then only after comparison and explicit caller approval request one verified unsigned session action. The provider itself still collects no wallet, creates no approval/session, and never signs or submits. The handoff is positioned for aggregate refill/material transfer, not automatic per-x402-micropayment top-up.

Revalidation at signed head d2643bb44f086d23cca440c509d89a145eb83704: TypeScript check passed, ESLint passed, Prettier passed, and all 19 AssetFare Jest tests passed.

[cb-heimdall]

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[cb-heimdall]

Review Error for MVPuknowme @ 2026-09-25 19:27:29 UTC
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