Clear crash-recovery draft on save, not just on discard

attemptSaveCurrentConversation() (Save/Save As) and confirmDiscardIfNeeded's
no-unsaved-changes early return both left the on-disk draft_conversation.json
untouched, so a stale snapshot from before the save lingered and triggered
"Restore unsaved conversation?" on next launch even though everything had
already been saved with no changes since.

oAI/ViewModels/ChatViewModel.swift

@@ -756,6 +756,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
             savedMessageCount = chatMessages.count
             notesEnabled = false
             notesFilename = nil
+            DraftRecoveryService.shared.clear()
             showSystemMessage("Saved as \"\(details.name)\"")
             Task { await GitSyncService.shared.autoSync() }
         } catch {
@@ -2359,7 +2360,14 @@ Don't narrate future actions ("Let me...") - just use the tools.
     /// discards the crash-recovery draft and proceeds; Cancel calls `onCancel()` — the caller's
     /// original action (new chat / clear / switch / quit) must not happen.
     func confirmDiscardIfNeeded(then proceed: @escaping () -> Void, onCancel: @escaping () -> Void = {}) {
-        guard hasUnsavedChanges else { proceed(); return }
+        guard hasUnsavedChanges else {
+            // Nothing unsaved means any on-disk crash-recovery draft is now stale (either a
+            // save already covered it, or there was nothing worth mirroring) — clear it so the
+            // next launch doesn't offer to "restore" a conversation that's already saved intact.
+            DraftRecoveryService.shared.clear()
+            proceed()
+            return
+        }
 
         let alert = NSAlert()
         alert.alertStyle = .warning
@@ -2401,6 +2409,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                     id: id, name: name, messages: chatMessages, primaryModel: selectedModel?.id
                 )
                 savedMessageCount = chatMessages.count
+                DraftRecoveryService.shared.clear()
                 showSystemMessage("Saved \"\(name)\"")
                 Task { await GitSyncService.shared.autoSync() }
                 return true
@@ -2421,6 +2430,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
             savedMessageCount = chatMessages.count
             notesEnabled = false
             notesFilename = nil
+            DraftRecoveryService.shared.clear()
             showSystemMessage("Saved as \"\(details.name)\"")
             Task { await GitSyncService.shared.autoSync() }
             return true