feat(web): management console frontend

Vue 3 + TS + Vite + Tailwind with self-built UI components. Landing,
auth, user dashboard (keys/usage/settings), and admin console
(overview/models/channels/users/usage/config). Theme system
(light/dark/system) with pre-paint boot script, theme-aware ECharts,
and a channel editor with multi-format (Anthropic/OpenAI) selection.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/tailwind.config.js

@@ -0,0 +1,45 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  content: ['./index.html', './src/**/*.{vue,ts,tsx}'],
+  theme: {
+    extend: {
+      colors: {
+        bg: 'rgb(var(--t-bg) / <alpha-value>)',
+        surface: {
+          DEFAULT: 'rgb(var(--t-surface) / <alpha-value>)',
+          2: 'rgb(var(--t-surface-2) / <alpha-value>)',
+        },
+        line: {
+          DEFAULT: 'rgb(var(--t-border) / <alpha-value>)',
+          strong: 'rgb(var(--t-border-strong) / <alpha-value>)',
+        },
+        ink: {
+          DEFAULT: 'rgb(var(--t-text) / <alpha-value>)',
+          soft: 'rgb(var(--t-text-soft) / <alpha-value>)',
+          mute: 'rgb(var(--t-text-mute) / <alpha-value>)',
+        },
+        brand: {
+          DEFAULT: 'rgb(var(--t-accent) / <alpha-value>)',
+          hover: 'rgb(var(--t-accent-hover) / <alpha-value>)',
+        },
+        ok: 'rgb(var(--t-success) / <alpha-value>)',
+        warn: 'rgb(var(--t-warning) / <alpha-value>)',
+        danger: 'rgb(var(--t-danger) / <alpha-value>)',
+        info: 'rgb(var(--t-info) / <alpha-value>)',
+      },
+      fontFamily: {
+        sans: 'var(--t-font-sans)',
+        mono: 'var(--t-font-mono)',
+      },
+      borderRadius: {
+        DEFAULT: 'var(--t-radius)',
+        sm: 'var(--t-radius-sm)',
+      },
+      boxShadow: {
+        card: 'var(--t-shadow-card)',
+        pop: 'var(--t-shadow-pop)',
+      },
+    },
+  },
+  plugins: [],
+}