Fix icon rendering, DB reload processing, and planner bugs

.gitignore

@@ -24,6 +24,9 @@ bin/
 .classpath
 .project
 
+# Claude
+CLAUDE.md
+
 # OS
 .DS_Store
 Thumbs.db

packaging/studysync.desktop

@@ -9,4 +9,4 @@ Icon=studysync
 Terminal=false
 Categories=Education;Office;ProjectManagement;
 Keywords=study;task;project;calendar;academic;planner;
-StartupWMClass=com-studysync-StudySyncApplication
+StartupWMClass=com.studysync.application.StudySyncJavaFXApp

scripts/install.sh

@@ -240,7 +240,7 @@ Icon=studysync
 Terminal=false
 Categories=Education;Office;ProjectManagement;
 Keywords=study;task;project;calendar;academic;planner;
-StartupWMClass=com-studysync-StudySyncApplication
+StartupWMClass=com.studysync.application.StudySyncJavaFXApp
 EOF
     else
         print_info "Using desktop file from: $desktop_source"

src/main/java/com/studysync/StudySyncApplication.java

@@ -7,6 +7,13 @@
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.ConfigurableApplicationContext;
 
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
 /**
  * Main entry point for the StudySync desktop application.
  * 
@@ -31,42 +38,80 @@ public class StudySyncApplication {
 
     /** The Spring application context instance shared across the application. */
     private static ConfigurableApplicationContext springContext;
-
+
+    /** File lock held for the lifetime of the process to enforce single-instance. */
+    @SuppressWarnings("unused") // must stay referenced to prevent GC releasing the lock
+    private static FileLock instanceLock;
+    @SuppressWarnings("unused")
+    private static RandomAccessFile lockRaf;
+
     /**
      * Main method that starts the StudySync application.
-     * 
-     * <p>This method performs the following initialization sequence:
-     * <ol>
-     *   <li>Configures system properties for JavaFX compatibility</li>
-     *   <li>Initializes the Spring Boot application context</li>
-     *   <li>Launches the JavaFX application with Spring integration</li>
-     * </ol></p>
-     * 
+     *
      * @param args command line arguments passed to both Spring Boot and JavaFX
      */
     public static void main(final String[] args) {
+        // Enforce single instance — exit immediately if another process holds the lock
+        if (!acquireInstanceLock()) {
+            System.err.println("StudySync is already running. Exiting.");
+            System.exit(1);
+        }
+
         // Disable Spring Boot's automatic shutdown when main method ends
         System.setProperty("java.awt.headless", "false");
-        
+
         // Attempt to sync Google Drive hosted data (if configured) before Spring initializes the database
         GoogleDriveBootstrap.initialize();
-        
+
         // Configure Spring Boot for faster startup
         SpringApplication app = new SpringApplication(StudySyncApplication.class);
-        
+
         // Enable lazy initialization for faster startup
         app.setLazyInitialization(true);
-        
+
         // Reduce startup output
         app.setLogStartupInfo(false);
         app.setBannerMode(org.springframework.boot.Banner.Mode.OFF);
-        
+
         // Start Spring Boot application context
         springContext = app.run(args);
-        
+
         // Launch JavaFX application
         Application.launch(StudySyncJavaFXApp.class, args);
     }
+
+    /**
+     * Attempts to acquire an exclusive file lock to prevent multiple instances.
+     * The lock file is created in the user's data directory and held for the
+     * lifetime of the JVM process (released automatically on exit).
+     *
+     * @return true if the lock was acquired (no other instance running)
+     */
+    private static boolean acquireInstanceLock() {
+        try {
+            Path lockDir = Path.of(System.getProperty("user.home"), ".local", "share", "studysync");
+            Files.createDirectories(lockDir);
+            Path lockFile = lockDir.resolve(".studysync.lock");
+
+            // RandomAccessFile + FileLock held in static fields so GC cannot release them
+            lockRaf = new RandomAccessFile(lockFile.toFile(), "rw");
+            FileChannel channel = lockRaf.getChannel();
+            instanceLock = channel.tryLock();
+
+            if (instanceLock == null) {
+                // Another instance holds the lock — close the file before exiting
+                try { lockRaf.close(); } catch (IOException ignored) { }
+                lockRaf = null;
+                return false;
+            }
+            return true;
+        } catch (Exception e) {
+            // Catches IOException AND OverlappingFileLockException (from same-JVM
+            // re-entry, e.g. test harnesses calling main() twice).
+            System.err.println("Warning: could not check instance lock: " + e.getMessage());
+            return true; // allow startup if lock mechanism fails
+        }
+    }
 
     /**
      * Provides access to the Spring application context for JavaFX components.

src/main/java/com/studysync/application/StudySyncJavaFXApp.java

@@ -143,32 +143,40 @@ public void start(final Stage primaryStage) {
                         event.consume(); // Prevent immediate close
 
                         Alert alert = new Alert(Alert.AlertType.CONFIRMATION);
-                        alert.setTitle("Sync to Google Drive");
-                        alert.setHeaderText("Save changes to Google Drive?");
-                        alert.setContentText("Do you want to upload your latest data to Google Drive before exiting?");
+                        alert.setTitle("Exit StudySync");
+                        alert.setHeaderText("How would you like to exit?");
+                        alert.setContentText("Choose how to save your data before closing.");
 
-                        ButtonType buttonSave = new ButtonType("Save & Exit");
-                        ButtonType buttonExit = new ButtonType("Exit Only");
+                        ButtonType buttonDrive = new ButtonType("Push to Drive & Exit");
+                        ButtonType buttonLocal = new ButtonType("Save Locally & Exit");
+                        ButtonType buttonNoSave = new ButtonType("Exit without Saving");
                         ButtonType buttonCancel = new ButtonType("Cancel", ButtonBar.ButtonData.CANCEL_CLOSE);
 
-                        alert.getButtonTypes().setAll(buttonSave, buttonExit, buttonCancel);
+                        alert.getButtonTypes().setAll(buttonDrive, buttonLocal, buttonNoSave, buttonCancel);
 
                         Optional<ButtonType> result = alert.showAndWait();
 
                         if (result.isPresent()) {
-                            if (result.get() == buttonSave) {
-                                logger.info("User chose to save and exit");
+                            if (result.get() == buttonDrive) {
+                                logger.info("User chose to push to Drive and exit");
                                 driveService.setShutdownSaveEnabled(true);
                                 Platform.exit();
-                            } else if (result.get() == buttonExit) {
-                                logger.info("User chose to exit without saving to Drive");
+                            } else if (result.get() == buttonLocal) {
+                                logger.info("User chose to save locally and exit");
+                                driveService.saveLocally();
+                                driveService.setShutdownSaveEnabled(false);
+                                Platform.exit();
+                            } else if (result.get() == buttonNoSave) {
+                                logger.info("User chose to exit without saving");
                                 driveService.setShutdownSaveEnabled(false);
                                 Platform.exit();
                             } else {
                                 logger.info("User cancelled exit");
                             }
                         }
                     } else {
+                        // Not signed in — flush H2 to disk and exit
+                        driveService.saveLocally();
                         Platform.exit();
                     }
                 } catch (Exception e) {

src/main/java/com/studysync/config/DatabaseReloadService.java

@@ -162,6 +162,18 @@ public void reconnect() {
             }
         }
 
+        // Evict the validation connections so that subsequent queries from
+        // panels/services go through brand-new connections.  Without this,
+        // the connections used during the retry loop above might still be
+        // in the pool and could serve cached data from the old H2 engine.
+        if (dataSource instanceof HikariDataSource hikari) {
+            HikariPoolMXBean pool = hikari.getHikariPoolMXBean();
+            if (pool != null) {
+                pool.softEvictConnections();
+                logger.debug("Post-reconnect: evicted validation connections from pool");
+            }
+        }
+
         // Run idempotent schema.sql to apply any missing migrations
         runMigrations();