WURK agent-to-human x402 connector + daemon wiring

[mizuki0x]

Agent-to-human microjobs for Covenant: agents hire vetted humans to review work, paid per winner in USDC over x402. Scope is the agent-to-human family only; the engagement/vote endpoints are unreachable through this crate.

What's here

• covenant-wurk crate: the x402 v2 pay loop, free submission view, creator-mode winner selection, and 3 MCP tools (wurk.hire_humans, wurk.job_status, wurk.choose_winners). 23 unit tests, parsers pinned to real fixtures.
• Daemon wiring: DaemonWurkExecutor in covenantd. Paid create routes through budget/settlement/audit and the x402 signer sidecar; view and choose-winners are free reads. Gated by COVENANT_WURK_ENABLED.

WURK quirks handled (reverse-engineered from x402-core, undocumented)

• Retry the payment against the job-specific resource.url; a fresh job is minted per create GET, so retrying the create URL mismatches the signed requirement.
• x402 v2 payload with the chosen requirement echoed into accepted (the matcher deepEquals it), the PAYMENT-SIGNATURE header, and the PayAI-sponsored feePayer.
• Signing reuses covenant-x402's PayaiSolanaSigner sidecar; covenant-wurk extracts the signed tx and re-wraps it in the v2 payload, so covenant-x402 is unchanged.

Verified

Crate + daemon unit tests pass. Live on mainnet: created and settled a real agent-to-human job end to end, transaction finalized on-chain, $0.01 USDC debited from the treasury.

Note: CI fmt is red on pre-existing workspace files, unrelated to this change.