Replace axios with native fetch in webhook utils

axios was required by src/utils/message.js and src/utils/webhook.js but was
never declared in package.json, so `npm install` never fetched it and the app
crashed on startup with MODULE_NOT_FOUND.

Switch both webhook POST calls to Node's built-in fetch (available since
Node 18; running on 22.12), removing the missing dependency entirely.
Behavior is preserved: JSON body with Content-Type header, and an explicit
response.ok check to keep axios's throw-on-non-2xx semantics. message.js now
returns parsed JSON (or text fallback) in place of axios's response.data.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/utils/message.js

@@ -1,4 +1,3 @@
-const axios = require('axios');
 const logger = require('./logger');
 
 // Function to send a note to a webhook
@@ -18,10 +17,21 @@ async function publishNoteWithKey(content, relays, privateKeyHex) {
         }
 
         // Send the payload to the webhook
-        const response = await axios.post(webhookUrl, payload);
+        const response = await fetch(webhookUrl, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify(payload)
+        });
+        if (!response.ok) {
+            throw new Error(`Webhook responded with status ${response.status}`);
+        }
         logger.info(`✅ Successfully sent note to webhook: ${response.status}`);
 
-        return response.data; // Assuming the webhook returns some data
+        // Parse JSON if the webhook returns it, otherwise fall back to text
+        const contentType = response.headers.get('content-type') || '';
+        return contentType.includes('application/json')
+            ? await response.json()
+            : await response.text();
     } catch (error) {
         logger.error('Error sending note to webhook:', error);
         throw error;

src/utils/webhook.js

@@ -1,4 +1,3 @@
-const axios = require('axios');
 const logger = require('./logger');
 
 // Function to send webhook notifications
@@ -10,10 +9,14 @@ async function sendWebhookNotification(action, data) {
     }
 
     try {
-        await axios.post(webhookUrl, {
-            action,
-            data
+        const response = await fetch(webhookUrl, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ action, data })
         });
+        if (!response.ok) {
+            throw new Error(`Webhook responded with status ${response.status}`);
+        }
         logger.info(`Webhook notification sent for action: ${action}`);
     } catch (error) {
         logger.error('Failed to send webhook notification:', error);