fix: hud not appearing after setup without restart (#213)

[learnabhi]

Fix: HUD not appearing after setup without restart

Closes #213

Problem

• Setup completes successfully but HUD doesn't appear in the same session
• Step 5 asks "is it working?" in the same session where it can never work
• No mention of restart requirement anywhere in the setup flow

Changes

Setup skill (/claude-hud:setup)

• Step 3: Prompt user to restart Claude Code immediately after config is written
• Step 5: Confirm user has restarted before asking if HUD is working
• Step 5 debug list: Add restart as first troubleshooting step (most common cause on macOS)

README.md

• Added note that Claude Code restart is required on macOS for statusLine config to take effect

index.ts

• Log restart hint when running without stdin on macOS

tests/integration.test.js

• Updated CLI prints initializing message on empty stdin assertion to use startsWith instead of strict equality — prevents breakage on non-macOS CI where the extra restart hint line is not printed