fix: add input validation and safe JSON parsing across 13 CLIs

Add missing parameter validation to prevent /path/undefined API calls:
- dub: require --url for links create
- google-search-console: require --sitemap-url for sitemaps submit
- kit: validate IDs and emails for subscribers, forms, sequences, tags, broadcasts
- mailchimp: validate IDs for lists get, campaigns get/create/send, members add, reports get
- resend: validate --from/--to/--subject for send, audience/contact IDs for contacts
- rewardful: validate IDs for affiliates get/update, commissions get, links create
- semrush: require --domain/--phrase for all domain and keyword commands
- sendgrid: validate --from/--to/--subject for send, campaign IDs, email for validate

Wrap bare JSON.parse() calls in try/catch for user-provided JSON:
- dub (--links), ga4 (--params), kit (--fields x4), mixpanel (--properties x2),
  onesignal (--filters), paddle (--scheduled-change, --items x2),
  resend (--emails, --variables x2), segment (--properties, --traits, --events),
  sendgrid (--template-data)

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

tools/clis/dub.js

@@ -58,6 +58,7 @@ async function main() {
     case 'links':
       switch (sub) {
         case 'create': {
+          if (!args.url) { result = { error: '--url required' }; break }
           const body = {}
           if (args.url) body.url = args.url
           if (args.domain) body.domain = args.domain
@@ -95,7 +96,12 @@ async function main() {
           result = await api('DELETE', `/links/${args.id}`)
           break
         case 'bulk-create': {
-          const links = JSON.parse(args.links || '[]')
+          let links
+          try {
+            links = JSON.parse(args.links || '[]')
+          } catch {
+            result = { error: 'Invalid JSON in --links' }; break
+          }
           result = await api('POST', '/links/bulk', links)
           break
         }