fix: auto-start commander on panel open

[web3dev1337]

Summary

• remove the stale Commander placeholder instructions that told users to click hidden Start buttons
• show a real "Starting" badge while the Commander shell is being launched
• rely on the backend's ready-based Claude auto-launch instead of a fragile client-side timeout on first open

Test Plan

• node --check client/commander-panel.js
• node --check tests/e2e/commander-paste.spec.js
• npm run test:unit -- --runTestsByPath tests/unit/commanderService.test.js tests/unit/commanderService.windowsShellArgs.test.js