fix(examples): use canonical /api/agent/vault/deposit endpoint

- Correct the preflight instructions to the two-phase single-endpoint
  flow (POST /api/agent/vault/deposit with {action: "intent"|"relay"}),
  matching the canonical FlipCoin Agent API / OpenAPI spec.
- Reference approvalRequired.operator for the ShareToken approval
  address (surfaced by the action provider).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: V.Talecky

typescript/examples/langchain-flipcoin-chatbot/README.md

@@ -28,8 +28,8 @@ pnpm start autonomous    # autonomous bettor mode
 
 Before the agent can trade you need:
 
-1. **USDC in the FlipCoin vault.** Deposit via `POST /api/agent/vault/deposit/intent` → sign → `/relay`. The agent-starter kit (https://github.com/flipcoin-fun/flipcoin-agent-starter) ships with a one-command helper.
-2. **ShareToken approval for sells only.** Call `ShareToken.setApprovalForAll(router, true)` once per chain from the trader wallet.
+1. **USDC in the FlipCoin vault.** Deposit via `POST /api/agent/vault/deposit` — first with `{ "action": "intent", "amount": "<raw-usdc-6-decimals>" }` to get EIP-712 typed data, sign it, then call the same endpoint again with `{ "action": "relay", "intentId": "<id>", "signature": "0x..." }`. The [agent-starter kit](https://github.com/flipcoin-fun/flipcoin-agent-starter) ships with a one-command helper.
+2. **ShareToken approval for sells only.** Call `ShareToken.setApprovalForAll(operator, true)` once per chain from the trader wallet. The exact `operator` address is returned in the intent response's `approvalRequired.operator` when approval is missing — the action provider surfaces it directly.
 
 ## Modes