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>

jetc/barant-site/src/main.page

@@ -2,28 +2,16 @@
 <title>BARANT Technology Group</title>
 <contents>
 <setenv name="_menubar"></setenv>
-<sectionframe title="Welcome to BARANT Systems">
-
-<div style="width: 48%;">
-  <p>We are BARANT Technology Group. Contact us for information on how we can
-     help you with your technical objectives.</p>
-
-  <h1>Modular1 VST Synthesizer</h1>
-  <p>Check out our <a href="/vst">Modular1 VST3
-Synthesizer</a> If you appreciate the art of modular analog
-synthesizers then you will really enjoy the Modular1 with all the
-features of an analog modular synthesizer put into a single VST3
-instrument. With the added features of polyphony and patches that
-change instantaneously this synthesizer is truly a powerhouse in the
-audio toolbox.</p>
-<a href="/vst"><img src="/assets/modular1.png" style="width: 200px;" align="left"></a>
-  <p>Excellent quality and technical performance provide a performance level
-instrument for musicians or students who wish to learn sound wave
-synthesis techniques or for musicians to enable that old analog sound 
-in their DAW recording system..</p>
- <p>Checkout the product page for more information on the capabilities
-of the Modular1 synthesizer.</p>
-</div>  
-</sectionframe>
+<div id="main-subpage">
+<if value1="$[SUBPAGE]" value2="" type="eq">
+ <include file="main-overview.subpage">
+<else>
+ <try>
+  <include file="main-$[SUBPAGE].subpage">
+ <catch>
+<p>That page doesn't exist.</p>
+ </try>
+</if>
+</div>
 </contents>
 </page>