Fix numerous thread/socket lifecycle crashes and TLS/epoll write-stall busy-loop

Thread/EPoll lifecycle:
- Thread::~Thread() now actually joins/frees its worker thread (was
  empty - the OS thread kept running against already-freed EPoll/Socket
  objects on any early teardown, a confirmed "double free" crash)
- EPoll::~EPoll() calls stop() if never explicitly stopped, for the
  same reason
- epoll_wait() now uses a 1s timeout instead of blocking forever, so a
  worker thread can actually notice isStopping() and let itself be
  joined
- EPoll::processCommand() iterated threads by value, silently
  double-freeing the real vector's Thread the moment each copy went
  out of scope
- ThreadScope gained onThreadStart()/onThreadEnd() hooks (actually
  wired up now - the constructor that was supposed to store the scope
  discarded it) for per-thread C-library init (e.g. MySQL client)

Socket/TCPSocket/TLS:
- Socket::writeSocket(): give up and shut down a connection after 50
  consecutive zero-progress sends instead of retrying forever -
  SSL_ERROR_WANT_READ on a write needs a READ to make progress, but
  resetSocket() re-arms EPOLLWRNORM regardless, which an
  already-writable TCP socket satisfies immediately - a real stuck
  connection generated 55GB, then 12.9GB of debug log this way before
  being caught
- Socket::writeSocket() now honors sendData()'s actual return value
  (previously discarded, entry popped unconditionally after one call) -
  a large response could get silently truncated past what fit in one
  write()/SSL_write() call
- TLS::registerSocket()/sendData()/receiveData(): `initialized` now
  only goes true once SSL_set_fd() has actually succeeded, and
  sendData()/receiveData() check it first - fixes a real SIGSEGV where
  a new session's own queued greeting could reach SSL_write() on a
  different epoll thread before this session's handshake setup had run
- TCPServer::connectionRequest() now performs the TLS handshake ON THE
  ACCEPTED SESSION, not the listening server itself (was building SSL
  state on the wrong object, leaving every session's own `ssl`
  uninitialized)
- TCPServer::receiveData() always uses the plain (non-TLS) read path -
  the listening socket is never itself a TLS peer
- TCPSocket's block-mode literal reading used an unset `blockLength`
  field instead of `blockSize`, and could busy-spin forever on a
  multi-packet literal
- TCPSocket line scanning replaced an unbounded strcspn() (assumes a
  NUL-terminated buffer; read past a non-NUL-terminated receive buffer
  into adjacent heap memory) with a bounds-checked memchr() scan

Protocol/session handling:
- CommandList::processRequest() now case-folds the command keyword
  before lookup - SMTP/POP3/IMAP commands are spec-required to be
  case-insensitive; a client sending "Mail From:" instead of
  "MAIL FROM:" previously failed to dispatch at all
- TCPSession::protocol() no longer drops blank lines while a handler
  has grabbed input (e.g. __SMTP_DATA reading a message body, an IMAP
  APPEND literal) - those handlers depend on seeing blank lines as
  real content, not commands; this silently corrupted any message body
  containing a blank line
- TCPSession's uuid alias fixed: streaming a raw uuid_t via operator<<
  triggered libstdc++'s unsigned-char* overload (strlen() on 16 binary
  bytes, a real stack-buffer-overflow read), and `alias` pointed at a
  stack-local that was already destroyed by the time the constructor
  returned
- INotify::processEvent() only treats event->name as a NUL-terminated
  string when event->len > 0 (per inotify(7)) instead of unconditional
  strlen() on a field the kernel doesn't guarantee is even present -
  a confirmed heap-buffer-overflow read that had been misdiagnosed as
  a MySQL thread-safety issue

EPoll.h

@@ -51,9 +51,13 @@ namespace core {
       ///
       /// @param numberOfThreads the number of threads to start for processing epoll entries.
       /// @param maxSockets the maximum number of open sockets that epoll will manage.
+      /// @param scope optional - if given, its onThreadStart()/onThreadEnd() run once on
+      ///   each worker thread, at the top/bottom of that thread's own lifetime. The SAME
+      ///   scope instance is shared across every worker thread - see ThreadScope's own
+      ///   doc comment. Not owned by EPoll; caller keeps it alive for the server's lifetime.
       ///
-      
-      bool start(int numberOfThreads, int maxSockets); ///< Start the BMAEPoll processing.
+
+      bool start(int numberOfThreads, int maxSockets, ThreadScope *scope = NULL); ///< Start the BMAEPoll processing.
       
       ///
       /// Use the stop() method to initiate the shutdown process for the epoll socket management.
@@ -103,6 +107,12 @@ namespace core {
       int numberOfThreads;
       std::vector<Thread> threads;
       volatile bool terminateThreads;
+      // Guards ~EPoll()'s own call to stop() - false until start()
+      // actually runs, so a never-started EPoll (numberOfThreads and
+      // threads both still default/empty) doesn't have its destructor
+      // iterate a garbage thread count. See ~EPoll()'s own doc comment
+      // in EPoll.cpp for what this is actually protecting against.
+      bool started;
 
    };