fix: G1 context registry — prevent empty contexts from dropping all export events

- Add ReadingContextRegistry for SessionManager→Pipeline context sharing
- Wire registry into SessionManager (register on open, unregister on close)
- Fix Pipeline to auto-pull from registry when contexts not provided
- Fix ScenePhase to not pass empty contexts

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

AIStudyApp/AIStudyApp/AIStudyAppApp.swift

@@ -71,14 +71,14 @@ struct AIStudyAppApp: App {
                     // Flush events: export → enqueue → (quick upload in background task)
                     Task {
                         let pipeline = ReadingEventUploadPipeline.shared
-                        pipeline.exportAndEnqueue(contexts: [:]) // contexts populated from active sessions
+                        pipeline.exportAndEnqueue() // pulls from ContextRegistry
                         await pipeline.flush()
                     }
                 case .active:
                     // Resume session + reload stale events from Rust
                     ReadingRuntimeSessionManager.shared.resume()
                     Task {
-                        ReadingEventUploadPipeline.shared.reloadOnLaunch(contexts: [:])
+                        ReadingEventUploadPipeline.shared.reloadOnLaunch()
                     }
                 case .inactive:
                     break

AIStudyApp/AIStudyApp/Features/MaterialReader/ReadingContextRegistry.swift

@@ -0,0 +1,22 @@
+import Foundation
+
+/// Shared registry of active reading material contexts.
+/// The SessionManager registers contexts here; the Pipeline reads them for export.
+@MainActor
+final class ReadingContextRegistry {
+    static let shared = ReadingContextRegistry()
+
+    private var contexts: [String: ReadingMaterialContext] = [:]
+
+    func register(_ context: ReadingMaterialContext) {
+        contexts[context.materialId] = context
+    }
+
+    func unregister(materialId: String) {
+        contexts.removeValue(forKey: materialId)
+    }
+
+    func allContexts() -> [String: ReadingMaterialContext] {
+        return contexts
+    }
+}

AIStudyApp/AIStudyApp/Features/MaterialReader/ReadingEventUploadQueue.swift

@@ -174,12 +174,13 @@ final class ReadingEventUploadPipeline {
 
     private init() {}
 
-    /// Full pipeline: export from Rust → enqueue.
-    func exportAndEnqueue(contexts: [String: ReadingMaterialContext]) {
+    /// Full pipeline: export from Rust → enqueue. Pulls contexts from registry if not provided.
+    func exportAndEnqueue(contexts: [String: ReadingMaterialContext] = [:]) {
+        let effectiveContexts = contexts.isEmpty ? ReadingContextRegistry.shared.allContexts() : contexts
         let rustEvents = adapter.exportEvents(limit: 100, timestampMs: nowMs())
         guard !rustEvents.isEmpty else { return }
 
-        let uploadItems = ReadingEventMapper.map(rustEvents: rustEvents, contexts: contexts)
+        let uploadItems = ReadingEventMapper.map(rustEvents: rustEvents, contexts: effectiveContexts)
         guard !uploadItems.isEmpty else { return }
 
         queue.enqueue(uploadItems)
@@ -214,7 +215,7 @@ final class ReadingEventUploadPipeline {
     }
 
     /// Reload on app launch: reload stale Rust events, enqueue, retry failed.
-    func reloadOnLaunch(contexts: [String: ReadingMaterialContext]) {
+    func reloadOnLaunch(contexts: [String: ReadingMaterialContext] = [:]) {
         _ = adapter.reloadStaleEvents()
         _ = adapter.cleanupStaleSessions(nowMs: nowMs(), maxAgeMs: 30 * 60 * 1000)
 

AIStudyApp/AIStudyApp/Features/MaterialReader/ReadingRuntimeSessionManager.swift

@@ -52,6 +52,7 @@ final class ReadingRuntimeSessionManager {
         activeSessionId = sessionId
         activeContext = context
         state = .active
+        ReadingContextRegistry.shared.register(context)
         lastPosition = nil
         lastHeartbeatAtMs = now
 
@@ -74,6 +75,7 @@ final class ReadingRuntimeSessionManager {
         _ = try? adapter.closeSession(sessionId)
 
         activeSessionId = nil
+        if let ctx = activeContext { ReadingContextRegistry.shared.unregister(materialId: ctx.materialId) }
         activeContext = nil
         lastPosition = nil
         state = .closed