Multi-day accumulated fixes: tag dispatch, session/pooling correctness, SPA rollout, jetc compiler

JetCore engine (Tag.cpp/.h, Global.cpp/.h, __*.cpp tag classes):
- Numerous __mysql.cpp connection-pooling correctness fixes (stale
  result sets, double-indirection sessionid bugs, field caching,
  pool keying) and a session-registration-before-connection-confirmed
  ordering fix (dangling pointer on a failed connect)
- Tag.cpp: large body of fixes to the tag-dispatch/container-scanning
  logic (bare-name fallback, database aliasing, single-quote handling,
  @-prefix session variable resolution, TAGDEF caching, nested split-tag
  scanning for if/while/until/ifrow so an inner one doesn't corrupt an
  outer one's own boundary scan) plus the process-first rendering
  order fix (a <process> now runs before <checksession>/page
  resolution, fixing a real "blank page after successful login" bug)
- Global.h/.cpp: added imapSessions (parallel to the existing __mysql*
  session map) for the new <imap> tag family
- __whiledir.cpp/__include.cpp: caching and directory-name-aliasing
  fixes
- __call.cpp/.h: fixed a dangling-pointer bug
- __write.cpp: fixed an O_WRONLY-only open that couldn't create a new
  file
- __ifrow.cpp/__sql.cpp: fixed the same sessionid double-indirection
  bug __mysql.cpp had (resolveKeyword's result was being used as a map
  key lookup instead of the resolved value itself)

jetc compiler (jetc/JetParser.cpp/.h, JetCodegen.cpp/.h, JetAST.h,
jetc.cpp, build-shared.sh, build-compiled.sh):
- Parser fixes: inline <include>, nested-quote handling, void-tag
  recognition
- Codegen fixes and expanded AST support
- build-shared.sh: atomic rename into place for a freshly-built .jtc
  (a live server dlopen()ing the same path mid-rebuild was corrupting
  its own already-mapped view of the old file) and a staleness check
  so a cached JetCore .o doesn't silently keep serving yesterday's
  fixes forever
- Added -lssl to both build scripts' link lines (needed once the new
  <imap> tag's client-side TLS code existed - previously nothing in
  this codebase used OpenSSL's SSL/TLS client API, only libcrypto)

Site content (jetc/barant-site/): SPA (fetch-and-swap navigation)
rollout across essentially every .page/.jet/.section/.tag/.proc/.method
file - dynamic-content fixes, fragment-mode stripping, native
$[@name] session variables replacing older mechanisms, and this
session's own checkout.page redesign, login start-param redirect fix,
and per-page side-menu (menu.bar/$[PAGE].menu) refresh support.
Completed the earlier main.css/control.css move from assets/ to
assets/images/ (git still showed the old paths as tracked-but-deleted
until now).

Deliberately left out of this commit: dozens of .pre-<description>-
<date> manual backup files (this session's and earlier ones' own
before/after snapshots, not meant for permanent history), compiled
.jtc build outputs, ad hoc test binaries and scripts under jetc/
(login_asan, wcwc_test, optest2_bin, etc.), and jetc/__pycache__/ -
none of these are meant to be tracked; a .gitignore covering them
would be worth adding separately.

__ifrow.cpp

@@ -6,17 +6,37 @@
 #include <unistd.h>
 
 namespace jet {
-   
+
    __ifrow::__ifrow(coreutils::ZString &in, coreutils::MString &parentOut, Global &global, Tag *parent, Tag *local) : Tag(in, parentOut, global, parent, this, "else") {
-      output = false;
+      // NOT setting output=false here (an earlier version of this file
+      // did) - that flag gates Tag::~Tag()'s own copyContainer(out,
+      // parentOut) call, the mechanism that propagates whatever
+      // processContainer() below actually wrote up to this tag's own
+      // caller. <ifrow>'s entire purpose is to conditionally DISPLAY one
+      // of its two branches (exactly like <if>/<while>/<until>, none of
+      // which ever touch `output`) - unlike the tags that legitimately
+      // do set it (<set>/<sql>/<cookie>/<header>/<write>/<tag>/
+      // <comment>/<stream>, none of which have any visible content of
+      // their own to emit), so setting it here silently discarded
+      // EVERY <ifrow>'s rendered content, true branch or false, on every
+      // single use. Confirmed live via gdb-style tracing: hasRow(),
+      // the resolved session pointer, and container's own text were all
+      // exactly correct at the point processContainer(container) ran -
+      // the content just never reached parentOut because the destructor
+      // skipped the copy. Never caught before because no real content
+      // this session exercised an <ifrow> with real row data AND had
+      // its rendered output actually inspected (account.page's own
+      // <ifrow sessionid="projman"> usage always redirected before
+      // reaching it, for lack of a login session).
       if(!hasContainer)
-	throw coreutils::Exception("ifrow tag must have a container.");	
-      if(!global.sessionExists(keywords[resolveKeyword("sessionid")]))
+	throw coreutils::Exception("ifrow tag must have a container.");
+      coreutils::MString sessionId = resolveKeyword("sessionid");
+      if(!global.sessionExists(sessionId))
 	throw coreutils::Exception("sessionid does not exist.");
-      if(global.getSession(keywords[resolveKeyword("sessionid")])->hasRow()) 
+      if(global.getSession(sessionId)->hasRow())
 	processContainer(container);
       else
 	processContainer(container2);
    }
-   
+
 }