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/main.cpp

@@ -19,6 +19,7 @@
 
 using namespace std;
 using namespace boost;
+namespace fs = boost::filesystem;
 
 //
 // Global state
@@ -2451,7 +2452,7 @@ bool CBlock::CheckBlockSignature() const
 
 bool CheckDiskSpace(uint64_t nAdditionalBytes)
 {
-    uint64_t nFreeBytesAvailable = filesystem::space(GetDataDir()).available;
+    uint64_t nFreeBytesAvailable = fs::space(GetDataDir()).available;
 
     // Check for nMinDiskSpace bytes (currently 50MB)
     if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
@@ -2467,7 +2468,7 @@ bool CheckDiskSpace(uint64_t nAdditionalBytes)
     return true;
 }
 
-static filesystem::path BlockFilePath(unsigned int nFile)
+static fs::path BlockFilePath(unsigned int nFile)
 {
     string strBlockFn = strprintf("blk%04u.dat", nFile);
     return GetDataDir() / strBlockFn;