Add global music player, invoicing/payment system, account subpages, mail account admin, and the qualityiron.vegas Jet 2.0 port

Jet interpreter (Tag.cpp, __call.cpp, __imap*.cpp/h, __smtpsend.cpp/h,
__imapemptyfolder.cpp/h - new): assorted parser/tag fixes found across
this work - a stray literal-tag-in-comment and backslash-quote parser
corruption class, a dangling-pointer fix, a __call.cpp fd leak, IMAP
folder-management tags, multi-account/per-host IMAP support, and a
smtpsend Message-ID fix.

barant.com site (jetc/barant-site/):
- A site-wide persistent music player (header band, playlist/queue,
  stereo FFT EQ, session-persisted state) fed by new library/
  ianslibrary/music song-list subpages.
- /account split into info/phones/invoices subpages; a full invoicing
  and Square payment system (create/edit/copy/pay/email invoice);
  admin invoice management and mail-account management subpages.
- /services split into overview/hosting/siptrunking/documents
  subpages, retiring the old standalone pages.
- SIPPHONE.tag: a Jet 2.0 WebRTC softphone tag.
- main.css/spa.js/email.js: the SPA loading indicator, the music
  player band styling, and assorted fixes accumulated alongside this
  work.

qualityiron-site/: the qualityiron.vegas job/contractor/customer/
document management app, ported from its original Jet 1.4 codebase to
Jet 2.0 as barant.coms APIServers second multi-tenant site.

wcwc/wcwc.jet: the WCWC site Jet source (wcwc.jtc build output not
included).

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

__smtpsend.cpp

@@ -10,6 +10,8 @@
 #include <cstdlib>
 #include <cstring>
 #include <ctime>
+#include <iomanip>
+#include <sstream>
 
 namespace jet {
 
@@ -88,10 +90,31 @@ namespace jet {
       return std::string(buf);
    }
 
+   // RFC 5322 3.6.4: Message-ID "SHOULD be present" - in practice
+   // several real receivers (confirmed live: Gmail) now hard-reject
+   // anything missing one ("550 5.7.1 Messages missing a valid
+   // Message-ID header are not accepted") rather than just marking it
+   // down, so this isn't optional in practice. Domain part is the
+   // sender's own domain (everything after '@' in `from`), matching
+   // RFC 5322's own recommendation that it be a name under the
+   // generating system's control - falls back to the literal `from`
+   // string in the (should-never-happen) case it has no '@' at all.
+   std::string __smtpsend::generateMessageId(const std::string &from) {
+      size_t at = from.find('@');
+      std::string domainPart = (at == std::string::npos) ? from : from.substr(at + 1);
+      struct timespec ts;
+      clock_gettime(CLOCK_REALTIME, &ts);
+      std::ostringstream idStream;
+      idStream << ts.tv_sec << "." << std::setfill('0') << std::setw(9) << ts.tv_nsec
+                << "." << rand() << "@" << domainPart;
+      return idStream.str();
+   }
+
    std::string __smtpsend::buildMessage(const std::string &from, const std::string &to,
                                          const std::string &subject, const std::string &html) {
       std::string msg;
       msg += "Date: " + rfc2822Date() + "\r\n";
+      msg += "Message-ID: <" + generateMessageId(from) + ">\r\n";
       msg += "From: " + from + "\r\n";
       msg += "To: " + to + "\r\n";
       msg += "Subject: " + subject + "\r\n";