perf: fix CPU overload on startup and clean up old cache data

- Limit concurrent file processing to max 4 tasks (was using all CPU cores)
- Add 1.5s startup delay before heavy processing begins
- Clean up ALL old UserDefaults permanent cache entries (was leaving hundreds)
- Increment cache version to 7 to force migration and cleanup
- Add 0.5s delay between providers during initial load

This prevents the app from becoming unresponsive on startup when processing
hundreds of Claude log files. The old implementation was using all CPU cores
and leaving massive amounts of data in UserDefaults.

Author: steipete

VibeMeter/Core/Services/ClaudeLogCacheManager.swift

@@ -13,7 +13,7 @@ public final class ClaudeLogCacheManager: @unchecked Sendable {
     private let cacheVersionKey = "com.vibemeter.claudeLogCacheVersion"
 
     // Cache schema version - increment this when parser format changes
-    private let currentCacheVersion = 6 // Incremented for database migration
+    private let currentCacheVersion = 7 // Force cleanup of old permanent cache entries
 
     // Cache validity duration
     private let cacheValidityDuration: TimeInterval = 300 // 5 minutes
@@ -340,21 +340,20 @@ public final class ClaudeLogCacheManager: @unchecked Sendable {
     private func migrateToDatabase() async {
         logger.info("Starting migration from UserDefaults to database")
 
-        // Clean up old UserDefaults keys
-        let oldKeys = [
-            "com.vibemeter.claudeLogCache",
-            "com.vibemeter.claudeFileHashCache",
-            "com.vibemeter.claudeLogPermanentCache",
-            "com.vibemeter.claudeLogPermanentCacheMetadata"
-        ]
+        // Clean up ALL old UserDefaults keys including individual permanent cache entries
+        let allKeys = userDefaults.dictionaryRepresentation().keys
+        var removedCount = 0
 
-        for key in oldKeys {
-            if userDefaults.object(forKey: key) != nil {
+        for key in allKeys {
+            if key.contains("claudeLog") || key.contains("claudeFileHash") {
                 userDefaults.removeObject(forKey: key)
-                logger.debug("Removed old UserDefaults key: \(key)")
+                removedCount += 1
             }
         }
 
-        logger.info("Migration complete - old UserDefaults cache cleared")
+        // Also remove the file hash cache
+        userDefaults.removeObject(forKey: "com.vibemeter.claudeFileHashCache")
+        
+        logger.info("Migration complete - removed \(removedCount) old UserDefaults cache entries")
     }
 }

VibeMeter/Core/Services/ClaudeLogProcessor.swift

@@ -53,18 +53,22 @@ actor ClaudeLogProcessor {
 
         let collector = ResultCollector(cache: cache)
 
-        // Use all available processors for maximum parallelism
-        let processorCount = ProcessInfo.processInfo.activeProcessorCount
-        logger.info("Processing \(fileURLs.count) log files using \(processorCount) processors")
+        // Limit concurrent tasks to prevent CPU overload
+        let maxConcurrentTasks = min(4, ProcessInfo.processInfo.activeProcessorCount)
+        logger.info("Processing \(fileURLs.count) log files using max \(maxConcurrentTasks) concurrent tasks")
 
-        // Process all files concurrently with TRUE parallelism
+        // Process files with controlled concurrency
         await withTaskGroup(of: ([ClaudeLogEntry], String, Data)?.self, returning: Void.self) { group in
-            // Add all tasks at once - Swift concurrency will manage the actual parallelism
-            for fileURL in fileURLs {
+            var fileIndex = 0
+            
+            // Start initial batch of tasks
+            for _ in 0..<min(maxConcurrentTasks, fileURLs.count) {
+                let fileURL = fileURLs[fileIndex]
                 group.addTask(priority: .background) { [self] in
                     // Process file without actor isolation to allow true parallelism
                     return await self.processFileParallel(fileURL, existingCache: cache, cacheManager: cacheManager)
                 }
+                fileIndex += 1
             }
 
             // Collect results as they complete
@@ -78,6 +82,15 @@ actor ClaudeLogProcessor {
                     await collector.incrementProcessedCount()
                 }
 
+                // Start next task if there are more files
+                if fileIndex < fileURLs.count {
+                    let fileURL = fileURLs[fileIndex]
+                    group.addTask(priority: .background) { [self] in
+                        return await self.processFileParallel(fileURL, existingCache: cache, cacheManager: cacheManager)
+                    }
+                    fileIndex += 1
+                }
+
                 // Send progress update every 10 files or on last file
                 let shouldUpdateProgress = processedCount % 10 == 0 || processedCount == fileURLs.count
 

VibeMeter/Core/Services/MultiProviderDataOrchestrator.swift

@@ -136,6 +136,9 @@ public final class MultiProviderDataOrchestrator {
 
         // Trigger initial data refresh for providers with existing tokens
         Task {
+            // Add a small delay to let the UI settle before heavy processing
+            try? await Task.sleep(nanoseconds: 1_500_000_000) // 1.5 seconds
+            
             let loggedInProviders = loginManager.loggedInProviders
             logger.info("Starting initial data refresh for \(loggedInProviders.count) logged-in providers")
 
@@ -146,6 +149,11 @@ public final class MultiProviderDataOrchestrator {
                     logger.info("Claude: Initial check - hasToken: \(hasToken)")
                 }
                 await refreshData(for: provider, showSyncedMessage: false)
+                
+                // Small delay between providers to prevent simultaneous heavy processing
+                if provider == .claude {
+                    try? await Task.sleep(nanoseconds: 500_000_000) // 0.5 seconds
+                }
             }
 
             // Start monitoring systems