Flag AI post-processing fallbacks in transcription history

Builds on altic-dev#279. After that PR a failed AI cleanup silently falls back
to the raw transcription with only a log line — a broken API key can
go unnoticed. This PR adds a durable visible signal.

Added `aiProcessingError: String?` to TranscriptionHistoryEntry
(Codable via decodeIfPresent — fully back-compat with existing
persisted history, old entries decode with nil). Threaded the
fallback reason into addEntry at the two dictation callsites.

UI:

- History list row shows an orange ⚠ triangle next to entries with
  a set aiProcessingError; hover reveals the error message.
- History detail view shows an orange callout card at the top with
  the full error message when the entry has one.

I also tried surfacing the failure as a transient message in the notch
overlay, but it was overridden by the post-typing overlay cleanup (the
NotchOverlayManager hide() that fires immediately after typing
completes), so that attempt is left as a follow-up.

Author: domdomegg

Sources/Fluid/ContentView.swift

@@ -1813,6 +1813,7 @@ struct ContentView: View {
         }
 
         var finalText: String
+        var aiFallbackReason: String?
 
         let shouldUseAI = activeDictationSlot.map { DictationAIPostProcessingGate.isConfigured(for: $0) } ??
             DictationAIPostProcessingGate.isConfigured()
@@ -1843,6 +1844,7 @@ struct ContentView: View {
                     "AI post-processing failed, falling back to raw transcription: \(error.localizedDescription)",
                     source: "ContentView"
                 )
+                aiFallbackReason = error.localizedDescription
                 finalText = transcribedText
             }
             let postProcessingLatencyMs = Int((Date().timeIntervalSince(postProcessingStart) * 1000).rounded())
@@ -1908,7 +1910,8 @@ struct ContentView: View {
                 rawText: transcribedText,
                 processedText: finalText,
                 appName: appInfo.name,
-                windowTitle: appInfo.windowTitle
+                windowTitle: appInfo.windowTitle,
+                aiProcessingError: aiFallbackReason
             )
         }
 
@@ -2118,6 +2121,7 @@ struct ContentView: View {
         await Task.yield()
 
         var finalText = transcribedText
+        var aiFallbackReason: String?
         let shouldUseAI = DictationAIPostProcessingGate.isConfigured()
         if shouldUseAI {
             do {
@@ -2127,6 +2131,7 @@ struct ContentView: View {
                     "AI reprocess failed, falling back to raw transcription: \(error.localizedDescription)",
                     source: "ContentView"
                 )
+                aiFallbackReason = error.localizedDescription
                 finalText = transcribedText
             }
         }
@@ -2142,7 +2147,8 @@ struct ContentView: View {
                 rawText: transcribedText,
                 processedText: finalText,
                 appName: appInfo.name,
-                windowTitle: appInfo.windowTitle
+                windowTitle: appInfo.windowTitle,
+                aiProcessingError: aiFallbackReason
             )
         }
 

Sources/Fluid/Persistence/TranscriptionHistoryStore.swift

@@ -19,14 +19,19 @@ struct TranscriptionHistoryEntry: Codable, Identifiable, Equatable {
     let windowTitle: String
     let characterCount: Int
     let wasAIProcessed: Bool
+    /// Non-nil when AI post-processing was configured but failed and we fell
+    /// back to typing the raw transcription. The string carries the error
+    /// message for display / debugging.
+    let aiProcessingError: String?
 
     init(
         id: UUID = UUID(),
         timestamp: Date = Date(),
         rawText: String,
         processedText: String,
         appName: String,
-        windowTitle: String
+        windowTitle: String,
+        aiProcessingError: String? = nil
     ) {
         self.id = id
         self.timestamp = timestamp
@@ -36,6 +41,25 @@ struct TranscriptionHistoryEntry: Codable, Identifiable, Equatable {
         self.windowTitle = windowTitle
         self.characterCount = processedText.count
         self.wasAIProcessed = rawText != processedText
+        self.aiProcessingError = aiProcessingError
+    }
+
+    init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        self.id = try container.decode(UUID.self, forKey: .id)
+        self.timestamp = try container.decode(Date.self, forKey: .timestamp)
+        self.rawText = try container.decode(String.self, forKey: .rawText)
+        self.processedText = try container.decode(String.self, forKey: .processedText)
+        self.appName = try container.decode(String.self, forKey: .appName)
+        self.windowTitle = try container.decode(String.self, forKey: .windowTitle)
+        self.characterCount = try container.decode(Int.self, forKey: .characterCount)
+        self.wasAIProcessed = try container.decode(Bool.self, forKey: .wasAIProcessed)
+        self.aiProcessingError = try container.decodeIfPresent(String.self, forKey: .aiProcessingError)
+    }
+
+    private enum CodingKeys: String, CodingKey {
+        case id, timestamp, rawText, processedText, appName, windowTitle
+        case characterCount, wasAIProcessed, aiProcessingError
     }
 
     /// Preview text for list display (first 80 chars)
@@ -95,7 +119,8 @@ final class TranscriptionHistoryStore: ObservableObject {
         rawText: String,
         processedText: String,
         appName: String,
-        windowTitle: String
+        windowTitle: String,
+        aiProcessingError: String? = nil
     ) {
         // Skip empty transcriptions
         guard !processedText.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else { return }
@@ -104,7 +129,8 @@ final class TranscriptionHistoryStore: ObservableObject {
             rawText: rawText,
             processedText: processedText,
             appName: appName,
-            windowTitle: windowTitle
+            windowTitle: windowTitle,
+            aiProcessingError: aiProcessingError
         )
 
         // Insert at beginning (newest first)

Sources/Fluid/UI/TranscriptionHistoryView.swift

@@ -143,6 +143,13 @@ struct TranscriptionHistoryView: View {
                             )
                     }
 
+                    if entry.aiProcessingError != nil {
+                        Image(systemName: "exclamationmark.triangle.fill")
+                            .font(.system(size: 10, weight: .bold))
+                            .foregroundStyle(isSelected ? .white : Color.orange)
+                            .help(entry.aiProcessingError ?? "")
+                    }
+
                     Spacer()
 
                     Text(entry.relativeTimeString)
@@ -294,6 +301,31 @@ struct TranscriptionHistoryView: View {
                 Divider()
                     .opacity(0.3)
 
+                if let aiError = entry.aiProcessingError {
+                    HStack(alignment: .top, spacing: 8) {
+                        Image(systemName: "exclamationmark.triangle.fill")
+                            .foregroundStyle(Color.orange)
+                        VStack(alignment: .leading, spacing: 2) {
+                            Text("AI cleanup failed — raw transcription was typed instead")
+                                .font(.system(size: 12, weight: .semibold))
+                            Text(aiError)
+                                .font(.system(size: 11))
+                                .foregroundStyle(.secondary)
+                                .textSelection(.enabled)
+                        }
+                    }
+                    .padding(10)
+                    .frame(maxWidth: .infinity, alignment: .leading)
+                    .background(
+                        RoundedRectangle(cornerRadius: 6, style: .continuous)
+                            .fill(Color.orange.opacity(0.08))
+                            .overlay(
+                                RoundedRectangle(cornerRadius: 6, style: .continuous)
+                                    .stroke(Color.orange.opacity(0.3), lineWidth: 1)
+                            )
+                    )
+                }
+
                 // Final Text Section
                 self.detailSection(
                     title: "Final Text",