perf: improve UI responsiveness during Claude log processing

- Batch progress updates to every 10 files instead of every file
- Add 0.5s debouncing to UI updates in ClaudeUsageDataLoader
- Increase default RealTimeMonitor interval from 30s to 60s
- Prevent excessive UI refreshes during log file processing

This significantly improves app responsiveness when processing hundreds
of Claude log files by reducing main thread UI updates.

Author: steipete

VibeMeter/Core/Services/ClaudeLogProcessor.swift

@@ -78,8 +78,10 @@ actor ClaudeLogProcessor {
                     await collector.incrementProcessedCount()
                 }
 
-                // Send progress update if handler provided
-                if let progressHandler {
+                // Send progress update every 10 files or on last file
+                let shouldUpdateProgress = processedCount % 10 == 0 || processedCount == fileURLs.count
+                
+                if let progressHandler, shouldUpdateProgress {
                     let (currentDailyUsage, _, currentFilesProcessed) = await collector.getResults()
                     await progressHandler(currentFilesProcessed, currentDailyUsage)
                 }

VibeMeter/Core/Services/RealTimeMonitor.swift

@@ -28,7 +28,7 @@ public final class RealTimeMonitor: ObservableObject {
         public let providers: [ServiceProvider]
 
         public static let `default` = Configuration(
-            updateInterval: 30, // 30 seconds
+            updateInterval: 60, // 60 seconds - reduced from 30 for better performance
             enableAnomalyDetection: true,
             enablePredictiveAlerts: true,
             burnRateThreshold: 10000, // tokens/hour

VibeMeter/Presentation/Views/ClaudeUsageReportModels.swift

@@ -157,6 +157,8 @@ final class ClaudeUsageDataLoader {
     var availableProjects: [String] = []
 
     private let claudeLogManager = ClaudeLogManager.shared
+    private var updateTimer: Timer?
+    private var pendingDailyUsage: [Date: [ClaudeLogEntry]]?
 
     func loadData(forceRefresh: Bool = false) {
         guard !isLoading else { return }
@@ -208,18 +210,31 @@ extension ClaudeUsageDataLoader: ClaudeLogProgressDelegate {
 
     func logProcessingDidUpdate(filesProcessed: Int, dailyUsage: [Date: [ClaudeLogEntry]]) {
         self.filesProcessed = filesProcessed
-        self.dailyUsage = dailyUsage
+        self.pendingDailyUsage = dailyUsage
 
         let percentage = totalFiles > 0 ? Int((Double(filesProcessed) / Double(totalFiles)) * 100) : 0
         self.loadingMessage = "Processing files... \(percentage)% (\(filesProcessed)/\(totalFiles))"
 
-        // Update available projects
-        updateAvailableProjects()
-
-        // Keep isLoading true - it will be set to false in logProcessingDidComplete
+        // Cancel existing timer
+        updateTimer?.invalidate()
+        
+        // Debounce the UI update by 0.5 seconds
+        updateTimer = Timer.scheduledTimer(withTimeInterval: 0.5, repeats: false) { [weak self] _ in
+            Task { @MainActor [weak self] in
+                guard let self = self, let pendingData = self.pendingDailyUsage else { return }
+                self.dailyUsage = pendingData
+                self.updateAvailableProjects()
+                self.pendingDailyUsage = nil
+            }
+        }
     }
 
     func logProcessingDidComplete(dailyUsage: [Date: [ClaudeLogEntry]]) {
+        // Cancel any pending timer
+        updateTimer?.invalidate()
+        updateTimer = nil
+        pendingDailyUsage = nil
+        
         self.dailyUsage = dailyUsage
         self.isLoading = false
         self.loadingMessage = ""