feat: persisted per-workspace panel zoom (proto + daemon, auto-clear on removal)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/spacesh-proto/src/message.rs

@@ -122,6 +122,11 @@ pub enum Cmd {
         limit: Option<u32>,
     },
     MarkRead { target: MarkReadTarget },
+    SetZoom {
+        workspace_id: WorkspaceId,
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        surface_id: Option<SurfaceId>,
+    },
     Health,
     Status,
     Shutdown,
@@ -322,6 +327,18 @@ mod tests {
         assert_eq!(back, evt);
     }
 
+    #[test]
+    fn set_zoom_cmd_round_trips() {
+        let z = Envelope::Req { id: 1, cmd: Cmd::SetZoom {
+            workspace_id: WorkspaceId("w_1".into()), surface_id: Some(SurfaceId("s_1".into())) } };
+        let j = serde_json::to_string(&z).unwrap();
+        assert!(j.contains(r#""cmd":"set_zoom""#));
+        assert_eq!(serde_json::from_str::<Envelope>(&j).unwrap(), z);
+        let unz = Envelope::Req { id: 2, cmd: Cmd::SetZoom {
+            workspace_id: WorkspaceId("w_1".into()), surface_id: None } };
+        assert_eq!(serde_json::from_str::<Envelope>(&serde_json::to_string(&unz).unwrap()).unwrap(), unz);
+    }
+
     #[test]
     fn health_cmd_round_trips() {
         let env = Envelope::Req { id: 1, cmd: Cmd::Health };

crates/spacesh-proto/src/workspace.rs

@@ -42,6 +42,9 @@ pub struct Workspace {
     /// None = empty workspace (no panels yet).
     #[serde(default)]
     pub layout: Option<LayoutNode>,
+    /// The single maximized surface for this workspace, if any.
+    #[serde(default)]
+    pub zoomed: Option<SurfaceId>,
     pub surfaces: HashMap<SurfaceId, SurfaceSpec>,
 }
 
@@ -66,6 +69,8 @@ pub struct WorkspaceView {
     pub order: u32,
     pub unread: bool,
     pub layout: Option<LayoutNode>,
+    #[serde(default)]
+    pub zoomed: Option<SurfaceId>,
     pub surfaces: HashMap<SurfaceId, SurfaceView>,
 }
 
@@ -99,10 +104,22 @@ mod tests {
             order: 0,
             unread: false,
             layout: None,
+            zoomed: None,
             surfaces: HashMap::new(),
         };
         let j = serde_json::to_string(&w).unwrap();
         let back: Workspace = serde_json::from_str(&j).unwrap();
         assert_eq!(back, w);
     }
+
+    #[test]
+    fn workspace_round_trips_with_zoom() {
+        let w = Workspace {
+            id: WorkspaceId("w_1".into()), path: "/tmp/p".into(), name: "p".into(),
+            group_id: None, order: 0, unread: false, layout: None,
+            zoomed: Some(SurfaceId("s_1".into())), surfaces: HashMap::new(),
+        };
+        let back: Workspace = serde_json::from_str(&serde_json::to_string(&w).unwrap()).unwrap();
+        assert_eq!(back, w);
+    }
 }