feat(v0.3): add Projects filter to ListWorkspaces; fix last/delete

ListOpts gains a Projects bool that filters by EffectiveType.
Default behavior (Projects: false) now returns tasks only --
this is a deliberate semantic change that supports the new
'ctask list' (tasks) vs 'ctask list --projects' (projects)
spec.

The change silently regresses two cmd-level callers that scan
for "the most recently updated workspace": cmd/last.go (used by
'ctask last') and cmd/delete.go (used to print the "this was
your most recent workspace" note). Both are fixed by unioning a
tasks-scan with a projects-scan, so 'last' and 'delete' continue
to consider both types.

Test helper createTestWorkspaceTyped allows setting an explicit
type (or "" to simulate a v0.2 workspace with no type field).

cmd/last.go

@@ -31,14 +31,25 @@ func init() {
 func runLast(cmd *cobra.Command, args []string) error {
 	root := config.ResolveRoot()
 
-	// Scan all non-archived workspaces and find the most recently updated
-	results, err := workspace.ListWorkspaces(root, workspace.ListOpts{
+	// Scan all non-archived workspaces (tasks AND projects) and find the most
+	// recently updated. v0.3: ListWorkspaces filters by type, so we union the
+	// two type buckets here so `last` keeps working for both.
+	tasks, err := workspace.ListWorkspaces(root, workspace.ListOpts{
 		IncludeArchived: false,
 		Limit:           0,
 	})
 	if err != nil {
 		return err
 	}
+	projects, err := workspace.ListWorkspaces(root, workspace.ListOpts{
+		IncludeArchived: false,
+		Projects:        true,
+		Limit:           0,
+	})
+	if err != nil {
+		return err
+	}
+	results := append(tasks, projects...)
 
 	if len(results) == 0 {
 		fmt.Fprintln(os.Stderr, "No active workspaces found.")