Black Pharao Release Fix 5 - OpenSSL 3.x and modern Boost compatibility

Port codebase to build with OpenSSL 3.x and Boost 1.90+:
- Rewrite bignum.h to use BIGNUM* pointer instead of inheriting from opaque BIGNUM
- Fix ECDSA_SIG, EVP_CIPHER_CTX, HMAC_CTX opaque type access across key.cpp, crypter.cpp, smessage.cpp
- Modernize Boost.Asio API (io_context, resolver, executor) in trianglesrpc.cpp
- Remove embedded Tor v2 client (incompatible with OpenSSL 3.x), keep Tor v3 SOCKS5 approach
- Update header logo to Cryptographic Triangles branding (300x63)
- Replace Bittrex exchange link with Pinball (313.cash) across all locales
- Fix MSYS2/MinGW64 build: linker flags, Boost library names, miniupnpc static linking

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/txdb-leveldb.cpp

@@ -22,6 +22,7 @@
 
 using namespace std;
 using namespace boost;
+namespace fs = boost::filesystem;
 
 leveldb::DB *txdb; // global pointer for LevelDB object instance
 
@@ -35,27 +36,27 @@ static leveldb::Options GetOptions() {
 
 void init_blockindex(leveldb::Options& options, bool fRemoveOld = false) {
     // First time init.
-    filesystem::path directory = GetDataDir() / "txleveldb";
+    fs::path directory = GetDataDir() / "txleveldb";
 
     if (fRemoveOld) {
-        filesystem::remove_all(directory); // remove directory
+        fs::remove_all(directory); // remove directory
         unsigned int nFile = 1;
 
         while (true)
         {
-            filesystem::path strBlockFile = GetDataDir() / strprintf("blk%04u.dat", nFile);
+            fs::path strBlockFile = GetDataDir() / strprintf("blk%04u.dat", nFile);
 
             // Break if no such file
-            if( !filesystem::exists( strBlockFile ) )
+            if( !fs::exists( strBlockFile ) )
                 break;
 
-            filesystem::remove(strBlockFile);
+            fs::remove(strBlockFile);
 
             nFile++;
         }
     }
 
-    filesystem::create_directory(directory);
+    fs::create_directory(directory);
     printf("Opening LevelDB in %s\n", directory.string().c_str());
     leveldb::Status status = leveldb::DB::Open(options, directory.string(), &txdb);
     if (!status.ok()) {