polish(v0.5.4): invocation-name audit + targeted regression tests

Audit walked every cmd/ and internal/ file that produces user-facing
output. All command-form hints (text the user is meant to type back)
were already routed through invocationName() in v0.5.3 — the audit is
a verification pass, not a code rewrite.

Additions:

- Extract formatResumeRestoreHint and formatDirectModeTmuxHint as
  testable string-only helpers. Production paths are unchanged
  behaviorally; the helpers exist purely so the audit can pin down
  the format strings without simulating tmux or stderr capture.

- Two new tests pinning the invocation name to a non-canonical value
  ("my-bin"). The pre-existing tests already protect these surfaces
  but pin the name to "ctask", so they cannot detect a regression
  that hard-codes "ctask" inside the format string. The new tests
  flush that out for the resume restore hint and the Layer-1
  active-session attach hint.

- Drop the duplicated withInvocationName helper accidentally added in
  the info-session tests; reuse the canonical helper from
  persistent_test.go.

Product-identity references ("ctask persistent mode requires tmux",
the SSH-remote `ssh -t <host> ctask <subcmd>` hint, doctor's "[ctask]"
diagnostic prefix, root-command Use:/Long:) deliberately remain
literal per spec §2.

cmd/entry.go

@@ -153,9 +153,17 @@ func directModeTmuxHint(opts WorkspaceEntryOptions) string {
 	if !shell.HasSession(tmuxPath, sessionName) {
 		return ""
 	}
+	return formatDirectModeTmuxHint(opts.WsMeta.Slug)
+}
+
+// formatDirectModeTmuxHint builds the hint string itself, with no tmux
+// or filesystem checks. Split out so unit tests can verify that the
+// command-form line uses invocationName() without needing a live tmux
+// session set up against a real workspace.
+func formatDirectModeTmuxHint(slug string) string {
 	return fmt.Sprintf(
 		"Tip: a tmux session exists for this workspace.\nTo reattach instead of starting a second direct-mode session, run:\n  %s attach %s",
-		invocationName(), opts.WsMeta.Slug)
+		invocationName(), slug)
 }
 
 func invokePersistentRun(opts WorkspaceEntryOptions, tmuxPath, sessionName string) error {

cmd/info_session_test.go

@@ -12,16 +12,7 @@ import (
 	"github.com/warrenronsiek/ctask/internal/workspace"
 )
 
-// withInvocationNameInfo pins invocationName() to "ctask" for the duration
-// of the test so attach-hint substring assertions are stable across hosts.
-// Mirrors the helper in persistent_test.go but kept local to avoid
-// cross-test coupling.
-func withInvocationNameInfo(t *testing.T, name string) {
-	t.Helper()
-	prev := invocationNameOverride
-	invocationNameOverride = name
-	t.Cleanup(func() { invocationNameOverride = prev })
-}
+// withInvocationName is provided by persistent_test.go in this package.
 
 // makeInfoSessionWorkspace writes a workspace under root with the given
 // slug and returns the workspace directory path. The workspace metadata
@@ -65,7 +56,7 @@ func TestInfoNoSession(t *testing.T) {
 }
 
 func TestInfoShowsActivePersistentSessionWithAttachHint(t *testing.T) {
-	withInvocationNameInfo(t, "ctask")
+	withInvocationName(t, "ctask")
 	root := t.TempDir()
 	wsDir := makeInfoSessionWorkspace(t, root, "active-persist")
 
@@ -95,7 +86,7 @@ func TestInfoShowsActivePersistentSessionWithAttachHint(t *testing.T) {
 }
 
 func TestInfoShowsActiveDirectSessionWithoutAttachHint(t *testing.T) {
-	withInvocationNameInfo(t, "ctask")
+	withInvocationName(t, "ctask")
 	root := t.TempDir()
 	wsDir := makeInfoSessionWorkspace(t, root, "active-direct")
 
@@ -124,7 +115,7 @@ func TestInfoShowsActiveDirectSessionWithoutAttachHint(t *testing.T) {
 }
 
 func TestInfoShowsRemoteHostnameInOwnerLine(t *testing.T) {
-	withInvocationNameInfo(t, "ctask")
+	withInvocationName(t, "ctask")
 	root := t.TempDir()
 	wsDir := makeInfoSessionWorkspace(t, root, "remote-active")
 

cmd/invocation_audit_test.go

@@ -0,0 +1,51 @@
+package cmd
+
+import (
+	"strings"
+	"testing"
+)
+
+// v0.5.4 invocation-name audit: spec §2 codifies that command-form
+// hints use invocationName() while product-identity references stay
+// literal. The pre-existing tests already cover most paths individually
+// (resume restore hint in resume_test.go, persistent bypass hints in
+// persistent_test.go). These tests pin down the remaining piece — the
+// Layer-1 active-session prompt's attach hint — and re-assert the
+// resume restore-hint contract against an explicitly non-canonical
+// invocation name so a regression that hard-codes "ctask" anywhere
+// upstream of the hint format will fail loudly.
+
+func TestInvocationNameInActiveSessionPrompt(t *testing.T) {
+	// directModeTmuxHint composes the Layer-1 prompt's attach suggestion
+	// from formatDirectModeTmuxHint. The format-only helper is the right
+	// surface to test: it isolates the rendering decision from the tmux
+	// presence checks (which are environment-dependent) but exercises the
+	// exact string the user will see.
+	withInvocationName(t, "my-bin")
+
+	got := formatDirectModeTmuxHint("demo-ws")
+
+	if !strings.Contains(got, "my-bin attach demo-ws") {
+		t.Errorf("Layer-1 attach hint should use invocation name; got:\n%s", got)
+	}
+	if strings.Contains(got, "ctask attach demo-ws") {
+		t.Errorf("Layer-1 attach hint must NOT hard-code 'ctask attach' when invocation name differs; got:\n%s", got)
+	}
+}
+
+func TestInvocationNameInRestoreHintNonCanonical(t *testing.T) {
+	// Complement to TestResumeArchivedShowsRestoreHint in resume_test.go,
+	// which pins invocationName to "ctask" — that protects against test
+	// binary noise but cannot detect a regression that hard-codes "ctask"
+	// in the format string. Pinning a non-default name flushes that out.
+	withInvocationName(t, "my-bin")
+
+	got := formatResumeRestoreHint("my-archived-ws")
+
+	if !strings.Contains(got, "my-bin restore my-archived-ws") {
+		t.Errorf("resume restore hint should use invocation name; got:\n%s", got)
+	}
+	if strings.Contains(got, "ctask restore") {
+		t.Errorf("resume restore hint must NOT hard-code 'ctask restore' when invocation name differs; got:\n%s", got)
+	}
+}

cmd/resume.go

@@ -58,9 +58,7 @@ func doResume(query string, container, useShell, force bool, agentOverride strin
 	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  %s restore %s\n",
-			query, invocationName(), query)
+		fmt.Fprint(os.Stderr, formatResumeRestoreHint(query))
 		return fmt.Errorf("workspace archived")
 	}
 
@@ -88,3 +86,19 @@ func doResume(query string, container, useShell, force bool, agentOverride strin
 		CommandName: "resume",
 	})
 }
+
+// formatResumeRestoreHint builds the multi-line stderr block printed
+// when `ctask resume <query>` resolves to an archived workspace.
+// Extracted so the v0.5.4 invocation-name audit can verify the
+// command-form line uses invocationName() without depending on the
+// surrounding fmt.Fprintf machinery.
+//
+// The "[ctask]" diagnostic prefix is intentionally a literal product
+// reference (spec §2: product-identity references stay literal). The
+// `restore <query>` line is the command-form portion and uses
+// invocationName().
+func formatResumeRestoreHint(query string) string {
+	return fmt.Sprintf(
+		"[ctask] error: workspace %q is archived\n\nTo restore it:\n  %s restore %s\n",
+		query, invocationName(), query)
+}