move and rename module

src/mail/actions/previous.py

@@ -0,0 +1,20 @@
+def action_previous(app) -> None:
+    """Show the previous email message by finding the next lower ID from the list of envelope IDs."""
+    try:
+        if app.reload_needed:
+            app.action_fetch_list()
+
+            ids = sorted(
+                (int(envelope["id"]) for envelope in app.all_envelopes), reverse=True
+            )
+            for envelope_id in ids:
+                if envelope_id < int(app.current_message_id):
+                    app.current_message_id = envelope_id
+                    app.show_message(app.current_message_id)
+                    return
+            app.show_status("No older messages found.", severity="warning")
+            app.action_oldest()
+        else:
+            app.show_status("Failed to fetch envelope list.", severity="error")
+    except Exception as e:
+        app.show_status(f"Error: {e}", severity="error")