Show current work (in_progress issues) in crew/polecat status bar

- Added GetPaneWorkDir to tmux package to get pane current directory
- Added getCurrentWork helper that queries beads for in_progress issues
- Worker status line now shows first in_progress issue (ID: title)
- Falls back to GT_ISSUE env var if set, or empty if no work in progress
- Truncated to 40 chars to fit status bar

Example: 👷 gt-44wh: Polecats must not create GitHu… |

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/tmux/tmux.go

@@ -207,6 +207,15 @@ func (t *Tmux) GetPaneCommand(session string) (string, error) {
 	return strings.TrimSpace(out), nil
 }
 
+// GetPaneWorkDir returns the current working directory of a pane.
+func (t *Tmux) GetPaneWorkDir(session string) (string, error) {
+	out, err := t.run("list-panes", "-t", session, "-F", "#{pane_current_path}")
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(out), nil
+}
+
 // CapturePane captures the visible content of a pane.
 func (t *Tmux) CapturePane(session string, lines int) (string, error) {
 	return t.run("capture-pane", "-p", "-t", session, "-S", fmt.Sprintf("-%d", lines))