fix: statusline setup nudge honors CLAUDE_CONFIG_DIR (#338)

The activation hook detects a missing statusline in getClaudeDir()/settings.json
(CLAUDE_CONFIG_DIR-aware) but the nudge text told the user and the agent to add
the statusLine config to ~/.claude/settings.json. With CLAUDE_CONFIG_DIR set,
that is the wrong file: Claude Code never reads it and the badge never turns on.
Point the nudge at the settingsPath the hook already computed, in both the
shell-safe and manual branches.

Fixes #250