feat(desktop): add buzz-agent-snapshot v1 export/import

desktop/src-tauri/src/commands/personas/mod.rs

@@ -972,3 +972,7 @@ pub async fn export_persona_to_json(
     let filename = format!("{slug}.persona.json");
     save_json_with_dialog(&app, &filename, &json_bytes).await
 }
+
+mod snapshot;
+pub use snapshot::export_agent_snapshot;
+pub use snapshot::{confirm_agent_snapshot_import, preview_agent_snapshot_import};

desktop/src-tauri/src/commands/personas/pending.rs

@@ -23,7 +23,11 @@ use crate::managed_agents::PersonaRecord;
 /// does not retain, so the local-only `is_active` toggle never republishes, and
 /// a byte-identical user-save republish is harmlessly NIP-33-replaced). The
 /// guard is intentionally omitted.
-pub(super) fn retain_persona_pending(app: &AppHandle, state: &AppState, persona: &PersonaRecord) {
+pub(in crate::commands::personas) fn retain_persona_pending(
+    app: &AppHandle,
+    state: &AppState,
+    persona: &PersonaRecord,
+) {
     use crate::managed_agents::{
         managed_agents_base_dir,
         persona_events::{build_persona_event, monotonic_created_at, persona_d_tag},