Fix display version to 5.5.6 + fix Tor binary path detection

DISPLAY_VERSION in version.h was still at 5.5.5 while CLIENT_VERSION
in clientversion.h was bumped to 5.5.6. Also fix Tor binary finder
to skip directories (was matching /usr/lib/.../tor/ dir instead of
the tor binary inside it).

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

src/tor/tor_process.cpp

@@ -129,9 +129,9 @@ std::string CTorProcess::FindTorBinary()
     candidates.push_back("/usr/local/opt/tor/bin/tor");
 #endif
 
-    // Check each candidate
+    // Check each candidate (must be a regular file, not a directory)
     for (const std::string& path : candidates) {
-        if (fs::exists(path)) {
+        if (fs::exists(path) && !fs::is_directory(path)) {
             printf("Found Tor binary at: %s\n", path.c_str());
             return path;
         }

src/version.h

@@ -53,7 +53,7 @@ static const int MEMPOOL_GD_VERSION = 60002;
 
 #define DISPLAY_VERSION_MAJOR       5
 #define DISPLAY_VERSION_MINOR       5
-#define DISPLAY_VERSION_REVISION    5
+#define DISPLAY_VERSION_REVISION    6
 #define DISPLAY_VERSION_BUILD       0
 
 #endif