Add web search knowledge base, message tagging, and word-memory tip topics

Introduces websearch.py (Tavily) + knowledge.py to ground chat responses
in search results, tagging.py to tag user and assistant messages via LLM
and pick related topics for the Discord useless-tips job, and
word_memory.py to track recent conversation nouns (surfaced in the new
WordPool.vue sidebar) used to pick tip topics close to a related tag.

frontend/src/components/ChatWindow.vue

@@ -2,10 +2,20 @@
 import { ref, watch, nextTick } from 'vue'
 import { useChatStore } from '../stores/chat'
 import MarkdownContent from './MarkdownContent.vue'
+import type { Source } from '../api/client'
 
 const store = useChatStore()
 const scrollEl = ref<HTMLElement | null>(null)
 
+function uniqueSources(sources: Source[]): Source[] {
+  const seen = new Set<string>()
+  return sources.filter((s) => {
+    if (seen.has(s.url)) return false
+    seen.add(s.url)
+    return true
+  })
+}
+
 watch(
   () => store.messages.length,
   async () => {
@@ -23,17 +33,36 @@ watch(
     <div
       v-for="(msg, i) in store.messages"
       :key="i"
-      :class="['message', msg.role, { error: msg.error }]"
+      :class="['message-wrap', msg.role]"
     >
-      <div class="bubble">
-        <!-- ユーザーメッセージはプレーンテキスト -->
-        <template v-if="msg.role === 'user'">{{ msg.content }}</template>
+      <div :class="['message', msg.role, { error: msg.error }]">
+        <div class="bubble">
+          <!-- ユーザーメッセージはプレーンテキスト -->
+          <template v-if="msg.role === 'user'">{{ msg.content }}</template>
 
-        <!-- アシスタントはMarkdownレンダリング -->
-        <template v-else>
-          <MarkdownContent :content="msg.content" :pending="msg.pending" />
-          <span v-if="msg.pending && !msg.content" class="cursor">▌</span>
-        </template>
+          <!-- アシスタントはMarkdownレンダリング -->
+          <template v-else>
+            <MarkdownContent :content="msg.content" :pending="msg.pending" />
+            <span v-if="msg.pending && !msg.content" class="cursor">▌</span>
+            <button v-if="msg.error" class="retry-btn" :disabled="store.isStreaming" @click="store.retryMessage(i)">
+              🔄 再送信
+            </button>
+          </template>
+        </div>
+      </div>
+      <div v-if="msg.tags && msg.tags.length > 0" class="tags">
+        <span v-for="tag in msg.tags" :key="tag" class="tag">#{{ tag }}</span>
+      </div>
+      <div v-if="msg.sources && msg.sources.length > 0" class="sources">
+        <span class="sources-label">🔍 参照元:</span>
+        <a
+          v-for="src in uniqueSources(msg.sources)"
+          :key="src.url"
+          :href="src.url"
+          target="_blank"
+          rel="noopener noreferrer"
+          class="source-link"
+        >{{ src.title || src.url }}</a>
       </div>
     </div>
   </div>
@@ -53,9 +82,50 @@ watch(
   color: #555;
   font-size: 14px;
 }
-.message { display: flex; }
+.message-wrap { display: flex; flex-direction: column; gap: 4px; }
+.message-wrap.user { align-items: flex-end; }
+.message-wrap.assistant { align-items: flex-start; }
+.message { display: flex; width: 100%; }
 .message.user { justify-content: flex-end; }
 .message.assistant { justify-content: flex-start; }
+.tags {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 6px;
+  max-width: 72%;
+}
+.tag {
+  font-size: 11px;
+  color: #93c5fd;
+  background: #1d3557;
+  border-radius: 10px;
+  padding: 2px 8px;
+}
+.sources {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 6px;
+  max-width: 72%;
+  font-size: 11px;
+}
+.sources-label {
+  color: #888;
+}
+.source-link {
+  color: #6ee7b7;
+  background: #103027;
+  border-radius: 10px;
+  padding: 2px 8px;
+  text-decoration: none;
+  max-width: 220px;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.source-link:hover {
+  text-decoration: underline;
+}
 .bubble {
   max-width: 72%;
   padding: 10px 14px;
@@ -84,5 +154,23 @@ watch(
   display: inline-block;
   animation: blink 0.8s step-end infinite;
 }
+.retry-btn {
+  display: block;
+  margin-top: 8px;
+  background: #2a1414;
+  color: #f87171;
+  border: 1px solid #7f1d1d;
+  border-radius: 6px;
+  padding: 4px 10px;
+  font-size: 12px;
+  cursor: pointer;
+}
+.retry-btn:hover:not(:disabled) {
+  background: #3b1a1a;
+}
+.retry-btn:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
+}
 @keyframes blink { 50% { opacity: 0; } }
 </style>