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/App.vue

@@ -8,6 +8,7 @@ import LogViewer from './components/LogViewer.vue'
 import ToastList from './components/ToastList.vue'
 import MemoryMonitor from './components/MemoryMonitor.vue'
 import Clock from './components/Clock.vue'
+import WordPool from './components/WordPool.vue'
 
 const showLogs = ref(false)
 </script>
@@ -17,6 +18,7 @@ const showLogs = ref(false)
     <div class="sidebar">
       <SessionList />
       <MemoryMonitor />
+      <WordPool />
     </div>
     <div class="main">
       <header>
@@ -49,7 +51,7 @@ body { background: #111; color: #eee; font-family: system-ui, sans-serif; }
 
 <style scoped>
 .app { display: flex; height: 100vh; }
-.sidebar { display: flex; flex-direction: column; border-right: 1px solid #333; overflow: hidden; }
+.sidebar { width: 260px; flex-shrink: 0; display: flex; flex-direction: column; border-right: 1px solid #333; overflow: hidden; }
 .main { flex: 1; display: flex; flex-direction: column; overflow: hidden; }
 header {
   display: flex; align-items: center; justify-content: space-between;