[codex] refine WebView UI layout

[T8numen]

Summary

• Initialize shared Codex project guidance in AGENTS.md.
• Refine the WebView UI shell, title/version area, left sidebar buttons, macro row columns, settings switch controls, and static help/reward/thanks pages.
• Keep built WebView assets and visual snapshots in sync with the React source changes.

Validation

• npm.cmd run build
• npm.cmd run test:visual:update
• powershell.exe -NoProfile -ExecutionPolicy Bypass -File .\scripts\verify.ps1 -AhkExe .\.tools\AutoHotkey\v2\AutoHotkey64.exe
• powershell.exe -NoProfile -ExecutionPolicy Bypass -File scripts\verify-webview-dist-sync.ps1
• git diff --check
• git diff --cached --check

Notes

• The default release path still uses WebViewApp/dist.
• Live UI development without rebuilding after every edit can use the existing Vite dev server path with RMT_WEBVIEW_DEV=1.