Add per-domain DKIM signing, admin console TLS, log rotation, and resolver timeout scoping

- DKIM signing was hardcoded to one domain; now keyed per-domain off
  the sending address, fixing mail for every domain but the original.
- Admin console (port 1027) is now TLS-wrapped instead of plaintext.
- barantmail.log now rotates by size (config-driven) instead of
  growing unbounded (previously hit 23GB).
- ResolverThreadScope.h: a <setenv> scoping fix for name resolution
  inside a <try> block that previously did not survive its own
  container.
- IMAPArgs.cpp: fixed "UID STORE 1:*" wrongly requiring UID 1 to
  exist, which silently made empty-folder operations delete nothing.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

BARANTMailConfig.cpp

@@ -82,20 +82,39 @@ namespace mail {
       return hasTls ? &tlsInfo : NULL;
    }
 
-   bool BARANTMailConfig::hasDkim() {
-      return file->exists("dkim.domain") && file->exists("dkim.selector") && file->exists("dkim.privateKey");
+   std::vector<BARANTMailConfig::DkimEntry> BARANTMailConfig::getDkimEntries() {
+      std::vector<DkimEntry> entries;
+      // No length-prefixed array accessor on JFile/JString - probe
+      // ascending indices via exists() (the same technique the JSON
+      // path syntax's own "a[2]" bracket form is meant for) until one
+      // is missing, matching a plain JSON array's natural "no trailing
+      // comma/count field" shape.
+      for (int i = 0; ; i++) {
+         std::string indexPrefix = "dkim[" + std::to_string(i) + "]";
+         std::string domainPath = indexPrefix + ".domain";
+         if (!file->exists(domainPath))
+            break;
+         std::string selectorPath = indexPrefix + ".selector";
+         std::string keyPath = indexPrefix + ".privateKey";
+         DkimEntry entry;
+         entry.domain = file->getString(domainPath);
+         entry.selector = file->getString(selectorPath);
+         entry.privateKeyPath = file->getString(keyPath);
+         entries.push_back(entry);
+      }
+      return entries;
    }
 
-   std::string BARANTMailConfig::getDkimDomain() {
-      return file->getString("dkim.domain");
+   bool BARANTMailConfig::hasLog() {
+      return file->exists("log");
    }
 
-   std::string BARANTMailConfig::getDkimSelector() {
-      return file->getString("dkim.selector");
+   size_t BARANTMailConfig::getLogMaxSizeBytes() {
+      return file->exists("log.maxSizeBytes") ? (size_t)file->getInt("log.maxSizeBytes") : 104857600;
    }
 
-   std::string BARANTMailConfig::getDkimPrivateKeyPath() {
-      return file->getString("dkim.privateKey");
+   int BARANTMailConfig::getLogMaxBackups() {
+      return file->exists("log.maxBackups") ? (int)file->getInt("log.maxBackups") : 5;
    }
 
    bool BARANTMailConfig::hasAdmin() {