Standardize response shapes and fix dead fetchT timeout keys

Three small cleanups for v1.14.0:

1. /caddy/cas now uses standard success envelope
   Was: { status: 'success', data: { cas: caList } }
   Now: { success: true, cas: caList }
   Updated frontend service-infrastructure.js to match.

2. /api/health/ca now uses standard envelope + meaningful HTTP codes
   Was: { status, message, daysUntilExpiration } with 200 on every error
   Now: { success, caStatus, message|error, daysUntilExpiration }
        with 200 / 404 / 500 as appropriate
   caStatus field preserves the original 'healthy'/'warning'/'critical'/'error'
   semantic so any future consumer of the CA-health state still has it.
   Tests updated to match.

3. Dead timeout: keys in fetchT opts are now a warning, not a silent strip
   src/utils/http.js:41 used to do  without telling
   anyone. Callers that wrote fetchT(url, { timeout: 5000 }) got the default
   5s timeout with no indication that their explicit value was ignored.
   Now it logs a warning naming the call site, then strips the key.
   Fixed 4 call sites that had stale timeout: keys:
   - src/context/caddy.js
   - src/context/dns.js
   - src/context/provider-dns.js
   - routes/dns.js (2 places)

status/js/core/service-infrastructure.js

@@ -14,15 +14,15 @@
 
       const result = await response.json();
 
-      if (result.status === 'success') {
+      if (result.success) {
         const select = document.getElementById('existing-ca-select');
         select.innerHTML = '';
 
-        if (result.data.cas.length === 0) {
+        if (result.cas.length === 0) {
           select.innerHTML = '<option value="">No CAs found in Caddyfile</option>';
         } else {
           select.innerHTML = '<option value="">Select existing CA...</option>';
-          result.data.cas.forEach(ca => {
+          result.cas.forEach(ca => {
             const option = document.createElement('option');
             if (typeof ca === 'object') {
               option.value = ca.id;