refactor: complete backend rewrite for multi-protocol proxy

Major rewrite of the Go backend to support:
- Three API format imports: openai, anthropic, compatible
- Three protocol conversions: Chat Completions, Responses, Messages
- Hub-and-spoke architecture with Chat as intermediate format

Deleted:
- opencat.go (old entry)
- store/, team/, pkg/team/, pkg/store/ (old data layer)
- internal/model/, internal/consts/ (old types)
- internal/service/team/, internal/controller/team/ (old handlers)
- llm/ (removed LLM client library, pure proxy mode)
- dist/, assets/ (old build artifacts)

Added:
- internal/store/ — 9 GORM models + multi-DB support
- internal/pkg/ — crypto (AES-GCM), apikey, jwt, ratelimit, resp, tokenizer
- internal/channel/ — channel selection, weighted LB, health checks
- internal/proxy/convert/ — 6 protocol conversion functions + SSE streaming
- internal/proxy/ — gateway with request dispatch and upstream selection
- internal/usage/ — async usage recorder with batch writes
- internal/api/ — management API (auth, users, keys, channels, models)
- Makefile for build/test/deploy

Fixed API to match frontend expectations:
- Login response wraps token in { data: { token } }
- GET /api/profile route added
- Profile response wraps user in { code, data }
- Role returned as number (10=admin, 1=user)

frontend/src/components/common/LineSegmentFlow.vue

@@ -1,7 +1,7 @@
 <template>
     <!-- 组件根元素：相对定位，设置最大宽度、外边距、宽高比、背景渐变、内边距、圆角、阴影和溢出隐藏 -->
     <div
-        class="relative w-full max-w-4xl mx-auto my-10 aspect-[4/3] backdrop-blur-0 px-4 py-0 my-0 rounded-lg  overflow-hidden ">
+        class="relative w-full max-w-4xl mx-auto my-10 aspect-[16/10] sm:aspect-[4/3] backdrop-blur-0 rounded-lg overflow-hidden ">
         <!-- bg-gradient-to-br from-slate-50 to-orange-50 -->
         <!-- 中心图标容器 -->
         <div ref="centerElement" class="absolute top-1/2 left-1/2 -translate-x-1/2 -translate-y-1/2 z-20">

frontend/src/views/Home.vue

@@ -47,7 +47,7 @@
               {{ star }}
             </span>
           </a>
-          <RouterLink to="/dashboard" class="btn btn-primary btn-sm h-9 min-h-9 rounded-full px-4">
+          <RouterLink to="/dashboard" class="btn btn-primary btn-sm h-9 min-h-9 rounded-full px-3 sm:px-4 whitespace-nowrap">
             Open Dashboard
           </RouterLink>
         </div>
@@ -60,7 +60,7 @@
         <img src="@/assets/openteam.png" alt="OpenTeam project logo" width="160" height="160" class="h-28 w-auto select-none" fetchpriority="high" />
         <h1 class="mt-4 text-4xl font-bold tracking-tight text-balance sm:text-5xl">OpenTeam</h1>
         <p class="mt-4 max-w-2xl text-pretty text-lg text-base-content/70">
-          An open-source, team-shared service compatible with the OpenAI API — share LLM API usage across your team through a single endpoint.
+          One endpoint for every model. Route OpenAI-compatible clients to any LLM provider — share costs, track usage, stay in control.
         </p>
 
         <div class="tooltip mt-8 w-full max-w-xl" data-tip="Point your client at the OpenTeam base URL">
@@ -78,6 +78,9 @@
           👉 Api-Keys:
           <a href="https://platform.openai.com/account/api-keys" class="link link-hover link-primary">platform.openai.com/account/api-keys</a>
         </p>
+        <p class="mt-3 text-sm text-base-content/60">
+          Connects to OpenAI, Claude, Gemini, DeepSeek and other OpenAI-compatible providers through a single endpoint.
+        </p>
       </section>
 
       <!-- How it works -->

frontend/src/views/dashboard/Profile.vue

@@ -164,7 +164,7 @@
                         </button>
                     </div>
 
-                    <div v-if="passkeys && passkeys.length" class="-mx-4 overflow-x-auto sm:-mx-6">
+                    <div v-if="passkeys && passkeys.length" class="overflow-x-auto">
                         <table class="table table-sm">
                             <thead>
                                 <tr class="text-xs uppercase tracking-wider text-base-content/50">

frontend/src/views/dashboard/Tokens.vue

@@ -25,7 +25,7 @@
           </thead>
           <tbody>
             <tr v-for="token in user.tokens" :key="token.id" class="border-base-300/40 hover:bg-base-200/50">
-              <td class="pl-4 font-medium">{{ token.name }}</td>
+              <td class="pl-4 font-medium truncate max-w-[120px] sm:max-w-[180px]">{{ token.name }}</td>
               <td>
                 <input type="checkbox" class="toggle toggle-success toggle-sm"
                   :class="!token.active && 'toggle-error'" v-model="token.active"

frontend/src/views/dashboard/UserView.vue

@@ -144,8 +144,8 @@
       <div class="card border border-base-300/60 bg-base-100 shadow-sm">
         <div class="card-body p-4 sm:p-5">
           <h3 class="card-title pb-1 text-base font-semibold">Tokens</h3>
-          <div v-if="user.tokens && user.tokens.length" class="-mx-4 overflow-x-auto sm:-mx-5">
-            <table class="table table-sm">
+          <div v-if="user.tokens && user.tokens.length" class="overflow-x-auto">
+            <table class="table table-sm min-w-[520px]">
               <thead>
                 <tr class="text-xs uppercase tracking-wider text-base-content/50">
                   <th class="pl-4">Token Name</th>