refactor(ios): migrate CrashReporter to ByteLystPlatformSDK's BLCrashReporter

Replaced standalone MetricKit crash reporter (153 lines) with thin wrapper (34 lines)
delegating to SDK's BLCrashReporter. Preserves existing call-site API.

ios/ChronoMind/Shared/Diagnostics/CrashReporter.swift

@@ -1,152 +1,33 @@
 // ── Crash Reporter ────────────────────────────────────────────
-// MetricKit-based crash and performance reporting for TestFlight/Production
+// Wrapper over ByteLystPlatformSDK's BLCrashReporter.
+// Preserves existing call-site API (CrashReporter.shared, loadCrashReports, clearReports).
 
 import Foundation
-import MetricKit
+import ByteLystPlatformSDK
+
+typealias CrashReport = BLCrashReport
 
 @MainActor
-final class CrashReporter: NSObject, ObservableObject, MXMetricManagerSubscriber {
+final class CrashReporter: ObservableObject {
     static let shared = CrashReporter()
 
     @Published var lastCrashReport: Date?
     @Published var diagnosticCount: Int = 0
 
-    private let persistenceKey = "chronomind-crash-reports"
+    private let reporter: BLCrashReporter
 
-    override private init() {
-        super.init()
-        MXMetricManager.shared.add(self)
-        loadStats()
-    }
-
-    deinit {
-        MXMetricManager.shared.remove(self)
-    }
-
-    // MARK: - MXMetricManagerSubscriber
-
-    nonisolated func didReceive(_ payloads: [MXMetricPayload]) {
-        // MetricKit delivers daily aggregated metrics
-        Task { @MainActor in
-            for payload in payloads {
-                processMetricPayload(payload)
-            }
-        }
-    }
-
-    nonisolated func didReceive(_ payloads: [MXDiagnosticPayload]) {
-        // Crash diagnostics — delivered after app restart following crash
-        Task { @MainActor in
-            for payload in payloads {
-                processDiagnosticPayload(payload)
-            }
-            self.diagnosticCount += payloads.count
-            self.lastCrashReport = Date()
-            self.saveStats()
-        }
-    }
-
-    // MARK: - Processing
-
-    private func processMetricPayload(_ payload: MXMetricPayload) {
-        // Log key performance metrics
-        if let launchTime = payload.applicationLaunchMetrics {
-            let resumeTime = launchTime.histogrammedResumeTime
-            logMetric("app_resume_time", histogram: resumeTime)
-        }
-
-        if let responsiveness = payload.applicationResponsivenessMetrics {
-            let hangTime = responsiveness.histogrammedApplicationHangTime
-            logMetric("hang_time", histogram: hangTime)
-        }
-    }
-
-    private func processDiagnosticPayload(_ payload: MXDiagnosticPayload) {
-        // Store crash data locally for feedback form
-        if let crashDiagnostics = payload.crashDiagnostics {
-            for crash in crashDiagnostics {
-                let report = CrashReport(
-                    date: Date(),
-                    exceptionType: crash.exceptionType?.description,
-                    signal: crash.signal?.description,
-                    terminationReason: crash.terminationReason?.description,
-                    callStackTree: crash.callStackTree.jsonRepresentation()
-                )
-                storeCrashReport(report)
-            }
-        }
-
-        if let hangDiagnostics = payload.hangDiagnostics {
-            for hang in hangDiagnostics {
-                let report = CrashReport(
-                    date: Date(),
-                    exceptionType: nil,
-                    signal: nil,
-                    terminationReason: "Hang: \(hang.hangDuration.description)",
-                    callStackTree: hang.callStackTree.jsonRepresentation()
-                )
-                storeCrashReport(report)
-            }
-        }
-    }
-
-    // MARK: - Storage
-
-    private func storeCrashReport(_ report: CrashReport) {
-        var reports = loadCrashReports()
-        reports.append(report)
-        // Keep last 50 reports
-        if reports.count > 50 {
-            reports = Array(reports.suffix(50))
-        }
-        if let data = try? JSONEncoder().encode(reports) {
-            UserDefaults.standard.set(data, forKey: persistenceKey)
-        }
+    private init() {
+        reporter = BLCrashReporter(productId: "chronomind")
+        diagnosticCount = reporter.diagnosticCount
+        lastCrashReport = reporter.lastCrashReport
     }
 
     func loadCrashReports() -> [CrashReport] {
-        guard let data = UserDefaults.standard.data(forKey: persistenceKey),
-              let reports = try? JSONDecoder().decode([CrashReport].self, from: data) else {
-            return []
-        }
-        return reports
+        reporter.loadCrashReports()
     }
 
     func clearReports() {
-        UserDefaults.standard.removeObject(forKey: persistenceKey)
+        reporter.clearReports()
         diagnosticCount = 0
     }
-
-    private func loadStats() {
-        diagnosticCount = loadCrashReports().count
-    }
-
-    private func saveStats() {
-        // Stats are derived from stored reports
-    }
-
-    private func logMetric(_ name: String, histogram: MXHistogram<UnitDuration>) {
-        // In production, send to analytics service
-        // For now, just track locally
-    }
-}
-
-// MARK: - Crash Report Model
-
-struct CrashReport: Codable, Identifiable {
-    let id: String
-    let date: Date
-    let exceptionType: String?
-    let signal: String?
-    let terminationReason: String?
-    let callStackData: Data?
-
-    init(date: Date, exceptionType: String?, signal: String?, terminationReason: String?, callStackTree: Data) {
-        self.id = UUID().uuidString
-        self.date = date
-        self.exceptionType = exceptionType
-        self.signal = signal
-        self.terminationReason = terminationReason
-        self.callStackData = callStackTree
-    }
 }