feat: rename project to DualFloatingClock, add README, public release

- Full rename: CMake target, bundle, LaunchAgent label
  (com.dualfloatingclock.clock), QSettings org/app, tray tooltip,
  icns resource, build scripts, CI workflows, sample config
- Config XML: new root DualFloatingClockConfig; reader accepts legacy
  ClouckConfig root for painless migration of existing settings
- README rewritten: fork provenance (ivaquero/clouck), features, build,
  tests, usage
- Drop stale README-CN.md

build.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 # Build script
 
-echo "Starting Clouck build..."
+echo "Starting DualFloatingClock build..."
 
 # Create build directory if it doesn't exist
 mkdir -p build
@@ -12,18 +12,18 @@ rm -rf build/*
 
 # Generate Makefile using qmake
 echo "Generating Makefile..."
-qmake Clouck.pro
+qmake DualFloatingClock.pro
 
 # Build project
 echo "Starting compilation..."
 make
 
 # Check build result
-if [ -f "build/Clouck.app/Contents/MacOS/Clouck" ] || [ -f "build/Clouck" ]; then
+if [ -f "build/DualFloatingClock.app/Contents/MacOS/DualFloatingClock" ] || [ -f "build/DualFloatingClock" ]; then
     echo "Build successful!"
     echo "Executable location:"
-    [ -f "build/Clouck.app/Contents/MacOS/Clouck" ] && echo "  - build/Clouck.app/Contents/MacOS/Clouck (macOS)"
-    [ -f "build/Clouck" ] && echo "  - build/Clouck (Linux)"
+    [ -f "build/DualFloatingClock.app/Contents/MacOS/DualFloatingClock" ] && echo "  - build/DualFloatingClock.app/Contents/MacOS/DualFloatingClock (macOS)"
+    [ -f "build/DualFloatingClock" ] && echo "  - build/DualFloatingClock (Linux)"
 else
     echo "Build failed!"
     exit 1