fix: correct API issues found by codex review across 10 CLIs

Fixes found by automated codex review of all 47 CLI tools:

- resend: webhook field name endpoint_url -> endpoint
- mailchimp: change from Bearer to Basic auth per API docs
- kit: fail fast when api_secret required but not set
- activecampaign: automation add-contact needs --contact-id not --email
- google-ads: budget updateMask must be snake_case (amount_micros)
- meta-ads: special_ad_categories default to ['NONE'] not empty array
- linkedin-ads: add required X-RestLi-Protocol-Version header
- onesignal: auth prefix should be Key, not Basic
- mixpanel: query dates must be YYYY-MM-DD, not relative strings
- wistia: change from Bearer to Basic auth per API docs

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

tools/clis/mailchimp.js

@@ -11,8 +11,9 @@ const dc = API_KEY.split('-').pop()
 const BASE_URL = `https://${dc}.api.mailchimp.com/3.0`
 
 async function api(method, path, body) {
+  const auth = 'Basic ' + Buffer.from(`anystring:${API_KEY}`).toString('base64')
   const headers = {
-    'Authorization': `Bearer ${API_KEY}`,
+    'Authorization': auth,
     'Content-Type': 'application/json',
   }
   if (args['dry-run']) {