feat(action-providers): add read-only TaskMarket discovery provider

[wilddoc]

Description

Adds a TaskMarket action provider so an agent can discover paid work on TaskMarket, a task marketplace where requesters escrow USDC on Base and workers submit deliverables.

The motivation is delegation. An agent that recognises a request is better handled by external workers can look for existing funded work instead of burning inference on something it will do badly, and can hand its operator a link rather than an unreliable answer.

Actions

Action	Purpose
browse_tasks	Lists open tasks by net reward, with deadline and how contested each already is
get_task_details	Full acceptance criteria, reward and award count for one task
evaluate_delegation	Given a description of work in hand, surfaces open tasks that overlap with it

Scope: read-only, on purpose

Nothing in this provider spends funds, touches a wallet, creates a task, claims work, or requires an API key.

Task creation and submission move real USDC through escrow, so they are deliberately left to the first-party TaskMarket CLI behind explicit human authorization rather than exposed as agent actions. evaluate_delegation states this in its own output: it returns candidates and says plainly that acting on them needs operator authorization.

Because of that, the provider needs no configuration and no secrets. The discovery endpoints are unauthenticated and read-only.

Design notes

• Rewards are reported net of the platform fee, which is what a worker actually receives.
• Submission counts are surfaced. A 64 USDC task with 142 submissions is often worth less in expectation than a 4 USDC task with three, and an agent recommending work should be able to see that.
• List views collapse descriptions to one line. Task descriptions run to hundreds of words of markdown and would otherwise dominate the context window.
• Matching uses transparent stopword-filtered keyword overlap, not embeddings, so it costs no extra model call and an operator can predict its behaviour.
• supportsNetwork returns true: browsing reads a public HTTP API and touches no wallet. Settlement is USDC on Base, but only once a user acts outside this provider.

Tests

taskmarketActionProvider.test.ts covers USDC base-unit conversion from both strings and numbers, hours-remaining parsing, description collapsing, reward-floor filtering, sorting by reward, delegation matching including the stopword and no-match paths, full task rendering, and the API-failure path (returns an error string rather than throwing).

One case worth calling out: a task can be status: "open" and already past its expiryTime. isOpenForWork checks status, submission window and expiry together, and there is a test for exactly that combination.

Checklist

• New action provider in its own directory following existing conventions
• Exported from action-providers/index.ts
• README documenting setup and scope
• Unit tests
• No new dependencies
• No secrets, keys or wallet access required

[cb-heimdall]

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