Add workspace CLI (list/add/remove) and registry hash/unregister

internal/workspace/registry.go

@@ -138,3 +138,43 @@ func (r *Registry) Find(hostPath string) mo.Option[Workspace] {
 	}
 	return mo.None[Workspace]()
 }
+
+// FindByHash looks up a workspace by its hash (or hash prefix)
+func (r *Registry) FindByHash(hash string) mo.Option[Workspace] {
+	for _, ws := range r.workspaces {
+		if ws.Hash == hash {
+			return mo.Some(ws)
+		}
+		// Also support prefix matching for convenience
+		if len(hash) >= 3 && len(hash) < 8 && ws.Hash[:len(hash)] == hash {
+			return mo.Some(ws)
+		}
+	}
+	return mo.None[Workspace]()
+}
+
+// Unregister removes a workspace from the registry by host path
+func (r *Registry) Unregister(hostPath string) bool {
+	absPath, err := filepath.Abs(hostPath)
+	if err != nil {
+		absPath = hostPath
+	}
+
+	if _, exists := r.workspaces[absPath]; exists {
+		delete(r.workspaces, absPath)
+		return true
+	}
+	return false
+}
+
+// UnregisterByHash removes a workspace from the registry by its hash
+func (r *Registry) UnregisterByHash(hash string) mo.Option[Workspace] {
+	wsOpt := r.FindByHash(hash)
+	if wsOpt.IsAbsent() {
+		return mo.None[Workspace]()
+	}
+
+	ws := wsOpt.MustGet()
+	delete(r.workspaces, ws.HostPath)
+	return mo.Some(ws)
+}