Preserve shell window identity and state flags

Retain window IDs, urgency and floating state in shell snapshots. Decode known flags from raw bitfields so future bits do not erase existing state.

Add exact-ID activation, close and overview selection helpers, with snapshot and wire-level regression coverage.

shell/ferese-shell/src/main.rs

@@ -1295,11 +1295,14 @@ mod tests {
             }],
             workspaces: Vec::new(),
             windows: vec![WindowSnapshot {
+                id: 42,
                 workspace,
                 app_id: "dev.ferese.Test".to_owned(),
                 title: "Test".to_owned(),
                 focused: true,
+                urgent: false,
                 fullscreen: true,
+                floating: false,
             }],
         }
     }