[simplex,sdk]: support cross-chain fx, optimize gas estimation (#696)

Author: royvardhan

docs/content/developers/evm/filler.mdx

@@ -50,7 +50,9 @@ BasicFiller requires pre-positioned stablecoins on each destination chain.
 
 ### HyperFX
 
-HyperFX fills same-chain swaps between USD-pegged stablecoins (USDC/USDT) and a single configurable exotic token — for example, cNGN (a Nigerian naira stablecoin). It only processes orders where `source == destination`.
+HyperFX fills swaps between USD-pegged stablecoins (USDC/USDT) and a single configurable exotic token — for example, cNGN (a Nigerian naira stablecoin). It supports both **same-chain** and **cross-chain** orders.
+
+Same-chain orders (`source == destination`) are filled immediately without waiting for additional confirmations. Cross-chain orders use the configured **confirmation policy** for HyperFX to determine how many confirmations to wait for before bidding.
 
 Profit comes from two sources: the **bid/ask spread** on the exotic token, and **order fees** minus gas. The filler holds both stablecoins and the exotic token. When a user swaps stable→exotic the filler sells exotic at the ask price; when the user swaps exotic→stable the filler buys at the bid price. The spread between the two curves is the filler's margin per trade.
 
@@ -135,10 +137,10 @@ bundlerUrl = "https://api.pimlico.io/v2/56/rpc?apikey=YOUR_KEY"
 ### Confirmation Policy
 
 <Callout type="info">
-Confirmation policies only apply to BasicFiller. HyperFX submits bids via the coprocessor and does not use this setting.
+Confirmation policies are configured per strategy. Both BasicFiller and HyperFX can use confirmation policies for cross-chain orders.
 </Callout>
 
-Before processing an order, Simplex waits for enough block confirmations to guard against chain reorganizations. The number of confirmations scales with order value using a curve — small orders are processed quickly, large orders wait longer:
+Before processing a cross-chain order, Simplex waits for enough block confirmations to guard against chain reorganizations. The number of confirmations scales with order value using a curve — small orders are processed quickly, large orders wait longer. Same-chain orders always proceed without additional confirmation delay.
 
 ```toml lineNumbers
 [confirmationPolicies."1"]     # Ethereum Mainnet (~12s blocks)
@@ -163,6 +165,38 @@ points = [
 ]
 ```
 
+For HyperFX, you can configure confirmation policies in the same way. For example:
+
+```toml lineNumbers
+[[strategies]]
+type = "hyperfx"
+maxOrderUsd = "5000"
+
+[strategies.exoticTokenAddresses]
+"EVM-56"  = "0xExoticTokenAddressOnBsc"
+"EVM-137" = "0xExoticTokenAddressOnPolygon"
+
+[strategies.confirmationPolicies]
+# Chain IDs for HyperFX confirmation policy (same schema as BasicFiller)
+[strategies.confirmationPolicies."56"]    # BSC (~1s blocks)
+points = [
+    { amount = "1",   value = 3  },
+    { amount = "500", value = 6  },
+    { amount = "5000", value = 15 },
+]
+
+[strategies.confirmationPolicies."42161"] # Arbitrum (~0.25s blocks)
+points = [
+    { amount = "2",    value = 2  },
+    { amount = "1000", value = 5  },
+    { amount = "8000", value = 10 },
+]
+```
+
+<Callout type="warning">
+If HyperFX is configured without <code>[strategies.confirmationPolicies]</code>, Simplex logs a warning at startup and skips cross-chain orders for that strategy. Only same-chain HyperFX orders will be processed in that case.
+</Callout>
+
 ### Auto-Rebalancing
 
 <Callout type="info">

docs/content/developers/intent-gateway/simplex.mdx

@@ -309,6 +309,45 @@ export class CryptoUtils {
 		return result.result
 	}
 
+	/**
+	 * Sends multiple JSON-RPC requests to the bundler in a single HTTP call
+	 * using JSON-RPC 2.0 batch syntax.  Results are returned in the same order
+	 * as the input `requests` array.
+	 *
+	 * @throws If the bundler URL is not configured, the HTTP call fails, or any
+	 *   individual response contains an error.
+	 */
+	async sendBundlerBatch<T extends unknown[]>(
+		requests: { method: BundlerMethod; params: unknown[] }[],
+	): Promise<T> {
+		if (!this.ctx.bundlerUrl) {
+			throw new Error("Bundler URL not configured")
+		}
+
+		const body = requests.map((r, i) => ({
+			jsonrpc: "2.0" as const,
+			id: i + 1,
+			method: r.method,
+			params: r.params,
+		}))
+
+		const response = await fetch(this.ctx.bundlerUrl, {
+			method: "POST",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify(body),
+		})
+
+		const results = (await response.json()) as { id: number; result?: unknown; error?: { message?: string } }[]
+		results.sort((a, b) => a.id - b.id)
+
+		return results.map((r) => {
+			if (r.error) {
+				throw new Error(`Bundler error: ${r.error.message || JSON.stringify(r.error)}`)
+			}
+			return r.result
+		}) as T
+	}
+
 	/**
 	 * Encodes a list of calls into ERC-7821 `execute` calldata using
 	 * single-batch mode (`ERC7821_BATCH_MODE`).