Restyle the web UI as a dark trading terminal

- Single palette (web/src/styles/palette.ts) taken from the Stitch
  design, exposed as ap-* UnoCSS colors and --ap-* CSS variables and
  used for Element Plus dark theme overrides, KLineChart and the news
  iframe; zero radius, JetBrains Mono / Space Grotesk bundled locally
- New sidebar and header layout; trading page, plan card and analysis
  drawer follow the design; other pages use the same panels
- Status API reports today's closed trades, wins and net PnL, shown as
  today's PnL and win rate on the trading page

web/src/main.ts

@@ -1,6 +1,8 @@
 import { createPinia } from "pinia"
 import App from "@/App.vue"
 import { router } from "@/router"
+import "@fontsource-variable/jetbrains-mono"
+import "@fontsource-variable/space-grotesk"
 import "element-plus/dist/index.css"
 import "element-plus/theme-chalk/dark/css-vars.css"
 import "@/styles/index.css"