feat(v0.5.2): direct lookup includes archived; resume hint for archived

Apply the v0.5.2 lookup policy to the existing commands and wire
ValidArgsFunction hooks across the workspace-accepting surface.

info: drop the --all/-a flag entirely. Direct lookup is now
archived-inclusive by default — the user typed a name, so we find
the workspace and surface its status in the output. The Status
line already distinguishes active vs archived clearly.

resume: when targeting an archived workspace, fail with a useful
hint instead of letting the resolver report "not found":

  [ctask] error: workspace "X" is archived

  To restore it:
    ctask restore X

This is implemented by resolving archived-inclusive and rejecting
status==archived before any session-launch logic runs. Genuine
not-found and ambiguous-match behavior are unchanged.

Adds ValidArgsFunction hooks to archive (active), delete (active),
open (active), info (any), resume (active). Restore/notes/path
already have hooks from the previous commit. Shell completion now
covers the full direct-lookup surface.

cmd/open.go

@@ -27,6 +27,8 @@ var (
 func init() {
 	openCmd.Flags().BoolVarP(&openAll, "all", "a", false, "Include archived workspaces in query resolution")
 	openCmd.Flags().BoolVar(&openForce, "force", false, "Skip active-session and stale-workspace warnings")
+	// v0.5.2: completion offers active candidates only (see delete for rationale).
+	openCmd.ValidArgsFunction = completeWorkspaces(completionActive)
 	rootCmd.AddCommand(openCmd)
 }