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/resume.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"fmt"
+	"os"
 	"path/filepath"
 	"time"
 
@@ -32,6 +33,7 @@ func init() {
 	resumeCmd.Flags().BoolVar(&resumeShell, "shell", false, "Open shell instead of agent")
 	resumeCmd.Flags().StringVarP(&resumeAgent, "agent", "a", "", "Override agent command")
 	resumeCmd.Flags().BoolVar(&resumeForce, "force", false, "Skip active-session and stale-workspace warnings")
+	resumeCmd.ValidArgsFunction = completeWorkspaces(completionActive)
 	rootCmd.AddCommand(resumeCmd)
 }
 
@@ -47,7 +49,18 @@ func doResume(query string, container, useShell, force bool, agentOverride strin
 	}
 
 	roots := config.SearchRoots()
-	ws := resolveOne(roots, query, false)
+	// v0.5.2: resolve archived-inclusive so we can give a helpful hint when
+	// the user resumes an archived workspace. resolveOne still handles
+	// not-found and ambiguity exactly as before — this only changes which
+	// workspaces are reachable, not how lookup failures are reported.
+	ws := resolveOne(roots, query, true)
+
+	if ws.Meta.Status == "archived" {
+		fmt.Fprintf(os.Stderr,
+			"[ctask] error: workspace %q is archived\n\nTo restore it:\n  ctask restore %s\n",
+			query, query)
+		return fmt.Errorf("workspace archived")
+	}
 
 	// Update updated_at
 	now := time.Now().UTC().Truncate(time.Second)