Add AgentToll action provider

[tevfikefeaydin]

Description

Adds an AgentToll action provider: pay-per-call Base data over x402, paid in
USDC from the agent's wallet with no API keys or accounts.

AgentToll (https://agenttoll.app, open source MIT) is a Base-native data API
settled through the CDP facilitator. This provider exposes six typed actions:

• scout_new_base_tokens — pools launched on Base in the last ~24h, each with
  a safety verdict already attached ($0.008)
• check_base_token_safety — simulated buy & sell, taxes, owner powers,
  holder concentration ($0.002)
• get_base_wallet_portfolio — everything an address holds, valued in USD ($0.003)
• get_base_token_price — any Base token by contract address, priced from
  onchain DEX liquidity ($0.001)
• resolve_basename — name to address + records, or address to primary name ($0.001)
• get_market_brief — prices + Base gas + Fear & Greed in one call ($0.005)

Payment uses the same wallet-to-signer pattern as the existing x402 action
provider (walletProvider.toSigner() + registerExactEvmScheme), so no new
payment machinery is introduced. A request that fails is never charged —
settlement only happens when data is returned. Safety verdicts are
deliberately conservative: a check that could not run is never a "pass", and a
token too new to judge reports insufficient-data, never clear.

Compared to routing these calls through the generic x402 provider, the typed
actions give the model exact input schemas and descriptions of when to reach
for each tool, and require no service registration config.

Tests

Unit tests cover request building, query handling, error paths (non-ok
responses and network failures returned as structured errors, not throws),
network gating (base-mainnet only) and the base URL override:

pnpm test -- agenttoll

The underlying API paths and payment flow were verified against production
with real USDC settlements on Base mainnet via the same @x402/fetch +
registerExactEvmScheme client wiring this provider uses (e.g. settlement
0xc2bde164520f7bcc17bdc0778c3274a6494994c94938ef81291b73d053df5e94). Every
endpoint also answers unauthenticated with an x402 v2 quote for manual
inspection: curl -i https://agenttoll.app/api/base/scout.

[cb-heimdall]

🟡 Heimdall Review Status

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