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>

MailFolder.cpp

@@ -95,20 +95,48 @@ namespace mail {
       while (std::getline(in, line)) {
          if (line.empty())
             continue;
-         std::istringstream stream(line);
-         Message message;
-         std::string uidStr, dateStr, flagsBlob;
-         stream >> message.fileName >> uidStr >> dateStr;
-         std::getline(stream, flagsBlob);
-         // The flags blob (if any) is whatever's left after the third
-         // field, minus the single separating space istream>> already
-         // consumed up to.
-         if (!flagsBlob.empty() && flagsBlob[0] == ' ')
-            flagsBlob.erase(0, 1);
-         message.uid = (uint32_t)std::stoul(uidStr);
-         message.internalDate = (time_t)std::stoll(dateStr);
-         message.flags = splitFlags(flagsBlob);
-         mMessages.push_back(message);
+         try {
+            std::istringstream stream(line);
+            Message message;
+            std::string uidStr, dateStr, flagsBlob;
+            stream >> message.fileName >> uidStr >> dateStr;
+            std::getline(stream, flagsBlob);
+            // The flags blob (if any) is whatever's left after the third
+            // field, minus the single separating space istream>> already
+            // consumed up to.
+            if (!flagsBlob.empty() && flagsBlob[0] == ' ')
+               flagsBlob.erase(0, 1);
+            // A short/truncated line (a write cut off mid-flush by a
+            // crash or restart racing save() - which already logs that
+            // this exact failure mode is possible, see save() below)
+            // leaves uidStr/dateStr empty, and stoul/stoll throw
+            // std::invalid_argument on that - uncaught, that previously
+            // propagated all the way up through load() and every IMAP
+            // handler that calls it (SELECT, EXAMINE) into
+            // CommandList::processRequest()'s own generic catch-all,
+            // which silently swallowed it and sent NO response at all -
+            // indistinguishable from the server hanging, since the
+            // client just waits forever for a reply that was never
+            // coming. Confirmed live: a single truncated trailing line
+            // ("Seen", missing its filename/uid/date - the tail end of
+            // what should have been a real message line) in a real
+            // user's Inbox .imapindex made every single SELECT/EXAMINE
+            // of that folder hang the connection, indefinitely,
+            // deterministically, until this line was found and
+            // skipped. Catching here instead means one corrupt line is
+            // dropped (logged) rather than taking the whole folder
+            // load - and therefore the whole command - down; the
+            // in-memory message list this produces is what save() (also
+            // called at the end of load(), unconditionally) rewrites
+            // the index file from, so the corrupt line is
+            // self-healed away on the very next successful load().
+            message.uid = (uint32_t)std::stoul(uidStr);
+            message.internalDate = (time_t)std::stoll(dateStr);
+            message.flags = splitFlags(flagsBlob);
+            mMessages.push_back(message);
+         } catch (...) {
+            coreutils::Log(coreutils::LOG_EXCEPT) << "MailFolder: skipping malformed .imapindex line in " << path << ": [" << line << "]";
+         }
       }
    }