Add NEAR wallet and x402 support

[mikedotexe]

Summary

• add a local-key NearWalletProvider with native balance/transfer, contract calls, NEP-141 balance/metadata/transfer helpers, and ClientNearSigner support
• add NEAR actions and extend the standard wallet actions for NEAR units
• register the @x402/near exact client scheme, Circle USDC metadata, and Solvador discovery
• document setup and add a patch changeset

The direct AgentKit x402 packages remain on 2.7 because @x402/svm 2.18 requires a newer incompatible Solana Kit. A real, unmocked compatibility test proves the 2.18 NEAR scheme creates a v2 payload through the existing 2.7 x402 client.

Validation

• full package suite: 64 suites and 888 tests passed
• typecheck, lint, build, format check, frozen offline install, and changeset validation passed
• focused NEAR suite: 20 tests, including recipient-storage and downstream receipt failures
• test:types is a pre-existing baseline failure because the configured src/tests/types.test-d.ts file is absent

Remaining launch gate

No funded testnet or mainnet transaction was sent from this environment. Live acceptance still needs a funded NEAR key, recipient storage registration, Solvador credentials for x402 settlement, and partner review.

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1