feat: DNS provider abstraction — Technitium, Cloudflare, RFC 2136, Manual

- dns-providers/: adapter base class + registry with auto-discovery
- technitium.js: wraps existing Technitium API calls into adapter interface
- cloudflare.js: Cloudflare API v4 adapter (zones, records, credentials)
- rfc2136.js: RFC 2136 dynamic DNS via nsupdate (BIND, PowerDNS, etc.)
- manual.js: no-op adapter for external DNS management with instructions
- provider-dns.js: provider-aware DNS context, resolves active adapter from config
- Universal helper methods: universalCreateRecord/Delete/ResolveRecord
- All 7 route files updated to use universal methods instead of raw dns.call()
- Setup wizard: provider dropdown (Technitium, Cloudflare, RFC 2136, Manual)
- DNS template selector: added Cloudflare and External/Manual options
- Config schema: validates dns.provider field
- Capability gating on Technitium-specific endpoints (logs, restart, update)
- Backward compatible: no provider set = auto-detect (technitium if dns.ip exists)

dashcaddy-api/routes/apps/deploy.js

@@ -316,7 +316,7 @@ module.exports = function({ docker, caddy, credentialManager, servicesStateManag
       let dnsWarning = null;
       if (config.createDns && !isSubdirectoryMode) {
         try {
-          await ctx.dns.createRecord(config.subdomain, config.ip);
+          await ctx.dns.universalCreateRecord(config.subdomain, config.ip);
           log.info('deploy', 'DNS record created', { domain: ctx.buildDomain(config.subdomain), ip: config.ip });
         } catch (dnsError) {
           await logError('app-deploy-dns', dnsError, { appId, subdomain: config.subdomain, ip: config.ip });

dashcaddy-api/routes/apps/removal.js

@@ -71,18 +71,13 @@ module.exports = function({
       if (shouldDeleteContainer && subdomain && ctx.dns.getToken()) {
         try {
           const domain = ctx.buildDomain(subdomain);
-          const getResult = await ctx.dns.call(ctx.siteConfig.dnsServerIp, '/api/zones/records/get', {
-            token: ctx.dns.getToken(), domain, zone: ctx.siteConfig.tld.replace(/^\./, ''), listZone: 'true'
-          });
+          const resolveResult = await ctx.dns.universalResolveRecord(domain, 'A');
           let recordIp = ip || 'localhost';
-          if (getResult.status === 'ok' && getResult.response?.records) {
-            const aRecord = getResult.response.records.find(r => r.type === 'A');
-            if (aRecord && aRecord.rData?.ipAddress) recordIp = aRecord.rData.ipAddress;
+          if (resolveResult) {
+            recordIp = resolveResult;
           }
-          const dnsResult = await ctx.dns.call(ctx.siteConfig.dnsServerIp, '/api/zones/records/delete', {
-            token: ctx.dns.getToken(), domain, type: 'A', ipAddress: recordIp
-          });
-          results.dns = dnsResult.status === 'ok' ? 'deleted' : (dnsResult.errorMessage || 'failed');
+          await ctx.dns.universalDeleteRecord(domain, recordIp);
+          results.dns = 'deleted';
           log.info('dns', 'DNS record removal', { result: results.dns });
         } catch (error) {
           results.dns = error.message;

dashcaddy-api/routes/apps/restore.js

@@ -458,7 +458,7 @@ module.exports = function({ docker, caddy, servicesStateManager, asyncHandler, e
     // DNS record
     if (manifest.config.createDns && manifest.caddy.routingMode !== 'subdirectory') {
       try {
-        await ctx.dns.createRecord(manifest.config.subdomain, manifest.config.ip);
+        await ctx.dns.universalCreateRecord(manifest.config.subdomain, manifest.config.ip);
         log.info('restore', 'DNS record recreated', { subdomain: manifest.config.subdomain });
       } catch (e) {
         log.warn('restore', `DNS recreation failed: ${e.message}`);

dashcaddy-api/routes/apps/templates.js

@@ -107,10 +107,8 @@ module.exports = function({
     if (oldSubdomain && ctx.dns.getToken()) {
       try {
         const oldDomain = oldSubdomain.includes('.') ? oldSubdomain : ctx.buildDomain(oldSubdomain);
-        const result = await ctx.dns.call(ctx.siteConfig.dnsServerIp, '/api/zones/records/delete', {
-          token: ctx.dns.getToken(), domain: oldDomain, type: 'A', ipAddress: ip || 'localhost'
-        });
-        results.oldDns = result.status === 'ok' ? 'deleted' : result.errorMessage;
+        await ctx.dns.universalDeleteRecord(oldDomain, ip || 'localhost');
+        results.oldDns = 'deleted';
         log.info('dns', 'Old DNS record deleted', { domain: oldDomain });
       } catch (error) {
         results.oldDns = `failed: ${error.message}`;
@@ -120,7 +118,7 @@ module.exports = function({
 
     if (newSubdomain && ctx.dns.getToken()) {
       try {
-        await ctx.dns.createRecord(newSubdomain, ip || 'localhost');
+        await ctx.dns.universalCreateRecord(newSubdomain, ip || 'localhost');
         results.newDns = 'created';
         log.info('dns', 'New DNS record created', { domain: ctx.buildDomain(newSubdomain) });
       } catch (error) {