feat(agentkit): add TaskMarket action provider

[brok-best]

Summary

Adds a TaskMarket action provider so AgentKit agents can discover USDC-escrowed work on Base and decide when to offer external delegation instead of burning local inference.

Actions

• list_open_tasks — browse open TaskMarket tasks (reward, competition, deadline)
• get_task — fetch one task by 0x id
• suggest_delegation — recommend offer_taskmarket / do_locally / need_user_budget

Safety

• Read/recommend only — no private keys, no auto create/claim/submit/spend
• Writes stay on TaskMarket CLI / user-authorized wallet flows
• Explicit notes against prompt-injection task creation

Why

TaskMarket is a natural complement to existing wallet + x402 providers: agents already decide when to spend; this surfaces when work should be delegated to escrowed workers.

Docs: https://taskmarket.dev/ · https://docs.taskmarket.dev/

Test plan

• Unit tests for utils + list/get/suggest (mocked fetch)
• cd typescript/agentkit && yarn test taskmarket (CI)
• Manual: wire taskmarketActionProvider() and call list_open_tasks

[cb-heimdall]

🟡 Heimdall Review Status

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