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.

__whilerow.cpp

@@ -6,16 +6,35 @@
 namespace jet {
 
    __whilerow::__whilerow(coreutils::ZString &in, coreutils::MString &parentOut, Global &global, Tag *parent, Tag *local) : Tag(in, parentOut, global, parent, local) {
-      
-      int count = keywords["count"].asInteger(); 
-      
-      while  ((count != 0) && global.getSession(keywords["sessionid"])->hasRow()) {	
+
+      // A bare <whilerow> (no count= attribute at all - the overwhelming
+      // majority of real usage: modular1_patches.page, account.page,
+      // task.page, project.page, editinvoice.page, musicianhome.page,
+      // invoice.method, modular1_1_preset_admin.page) used to default
+      // count to 0 - keywords["count"] auto-vivifies an empty string for
+      // a missing attribute, and "".asInteger() is 0 - which made the
+      // loop's own (count != 0) condition false on the very first check,
+      // before hasRow() was ever even consulted. Every one of those
+      // pages' row-based content silently rendered nothing, for every
+      // request, this entire session - never caught because nothing
+      // that exercised a bare <whilerow> with real row data also had its
+      // actual rendered output inspected until now. count= is meant as
+      // an OPTIONAL cap ("show at most N rows"); absent, it must mean
+      // unlimited, not zero - -1 as a sentinel keeps working with the
+      // existing (count != 0) loop test forever (decrementing through
+      // negative numbers never hits 0), letting hasRow() alone decide
+      // when the loop ends, exactly as bare usage always intended.
+      int count = keywordDefined("count") ? keywords["count"].asInteger() : -1;
+
+      __mysql *session = global.getSession(resolveKeyword("sessionid"));
+
+      while((count != 0) && session->hasRow()) {
 	 processContainer(container);
 	 container.reset();
-	 global.getSession(keywords["sessionid"])->nextRow();
+	 session->nextRow();
 	 --count;
       }
-      
+
    }
-   
+
 }