Add sending transactions section to autosign usage page

interwovenkit/features/autosign/usage.mdx

@@ -118,6 +118,60 @@ When `autoSign.enable()` is called:
 The method returns a Promise that resolves when autosign is successfully enabled
 or rejects if the user cancels or an error occurs.
 
+## Sending transactions with autosign
+
+Once autosign is enabled, you can send transactions without user confirmation
+using `submitTxBlock`. This method signs and broadcasts transactions directly
+using the ghost wallet.
+
+```tsx
+import { calculateFee, GasPrice } from '@cosmjs/stargate'
+import { MsgSend } from 'cosmjs-types/cosmos/bank/v1beta1/tx'
+import { useMutation } from '@tanstack/react-query'
+import { useInterwovenKit } from '@initia/interwovenkit-react'
+
+function SendWithAutosign() {
+  const { initiaAddress, submitTxBlock, estimateGas } = useInterwovenKit()
+
+  const { mutate, isPending } = useMutation({
+    mutationFn: async () => {
+      const messages = [
+        {
+          typeUrl: '/cosmos.bank.v1beta1.MsgSend',
+          value: MsgSend.fromPartial({
+            fromAddress: initiaAddress,
+            toAddress: 'init1...', // recipient address
+            amount: [{ amount: '1000000', denom: 'uinit' }],
+          }),
+        },
+      ]
+
+      // Estimate gas and calculate fee
+      const gasEstimate = await estimateGas({ messages })
+      const fee = calculateFee(
+        Math.ceil(gasEstimate * 1.4),
+        GasPrice.fromString('0.015uinit'),
+      )
+
+      // Submit transaction directly (no modal)
+      const { transactionHash } = await submitTxBlock({ messages, fee })
+      return transactionHash
+    },
+  })
+
+  return (
+    <button onClick={() => mutate()} disabled={isPending}>
+      Send
+    </button>
+  )
+}
+```
+
+<Tip>
+  Use `submitTxBlock` for seamless transactions with autosign. For transactions
+  requiring user confirmation, use `requestTxBlock` instead.
+</Tip>
+
 ## Disabling Autosign
 
 Users can disable autosign at any time. This revokes all grants for the selected