Re-embed the knowledge base when the embedding model changes

Vectors from two different embedding models are not comparable — Titan v2 has
1024 dimensions where nomic-embed-text has 768 — and _cosine_similarity zips
them, so a mismatch produced quietly meaningless scores rather than an error.
Nothing forced a re-embed either: sync_local_kb only looked at the content
hash, so switching models left every cached vector in place.

local_knowledge_docs now records the model each vector came from, and a row is
re-embedded when its content hash OR its model differs. Saving a new
LOCAL_KB_EMBEDDING_MODEL from the settings panel starts a background pass over
every file; the knowledge base panel also has a button for it. While that pass
runs, the per-request sync steps aside so no file is embedded twice.

The panel now shows what the embedding model is doing: model name, vector
size, how many files are embedded with the current model, how many are still
on an older one, a progress bar while a pass runs, and the last error. A
"接続テスト" button embeds one short string so a broken or unreachable model
can be told apart from one that is merely slow to warm up.

Also read TAVILY_API_KEY from os.environ at call time. It was imported as a
config constant, which is evaluated before load_into_env() runs, so a key
saved from the settings panel was stored but never used — not even after a
restart.

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

frontend/src/stores/knowledgeBase.ts

@@ -1,6 +1,16 @@
 import { defineStore } from 'pinia'
 import { computed, ref } from 'vue'
-import { fetchKbFile, fetchKbFiles, type KbFileContent, type KbFileInfo } from '../api/client'
+import {
+  fetchKbEmbeddingStatus,
+  fetchKbFile,
+  fetchKbFiles,
+  reindexKbEmbeddings,
+  testKbEmbedding,
+  type KbEmbeddingProbe,
+  type KbEmbeddingStatus,
+  type KbFileContent,
+  type KbFileInfo,
+} from '../api/client'
 
 export interface KbGroup {
   /** ナレッジベース直下は空文字。 */
@@ -18,6 +28,15 @@ export const useKnowledgeBaseStore = defineStore('knowledgeBase', () => {
   const filter = ref('')
   /** 折りたたまれているフォルダ名。web_search のようにファイル数が多いフォルダを畳むために使う。 */
   const collapsed = ref<Set<string>>(new Set())
+  /** 埋め込みモデルの状態と進捗。 */
+  const embedding = ref<KbEmbeddingStatus | null>(null)
+  /** 「接続テスト」の結果。 */
+  const probe = ref<KbEmbeddingProbe | null>(null)
+  const testing = ref(false)
+
+  /** 埋め込み実行中だけ状態をポーリングするタイマー。 */
+  let pollTimer: number | null = null
+  const POLL_INTERVAL_MS = 1500
 
   const filteredFiles = computed(() => {
     const q = filter.value.trim().toLowerCase()
@@ -66,6 +85,57 @@ export const useKnowledgeBaseStore = defineStore('knowledgeBase', () => {
     openFile.value = null
   }
 
+  /** 埋め込みの状態を取り直す。実行中ならポーリングを始め、終わっていれば止める。 */
+  async function loadEmbedding(): Promise<void> {
+    try {
+      embedding.value = await fetchKbEmbeddingStatus()
+    } catch (e) {
+      error.value = e instanceof Error ? e.message : '埋め込み状態の取得に失敗しました'
+      stopPolling()
+      return
+    }
+    if (embedding.value.running && pollTimer === null) {
+      pollTimer = window.setInterval(() => void loadEmbedding(), POLL_INTERVAL_MS)
+    } else if (!embedding.value.running && pollTimer !== null) {
+      stopPolling()
+      // 埋め込みが終わったので、一覧の「埋め込み済み」表示も更新する
+      await load()
+    }
+  }
+
+  function stopPolling(): void {
+    if (pollTimer !== null) {
+      clearInterval(pollTimer)
+      pollTimer = null
+    }
+  }
+
+  /** 埋め込みモデルに実際にリクエストして、応答するか確かめる。 */
+  async function testEmbedding(): Promise<void> {
+    testing.value = true
+    probe.value = null
+    try {
+      probe.value = await testKbEmbedding()
+    } catch (e) {
+      error.value = e instanceof Error ? e.message : '埋め込みテストに失敗しました'
+    } finally {
+      testing.value = false
+    }
+  }
+
+  /** 全ファイルの再埋め込みをバックグラウンドで開始する。 */
+  async function reindex(): Promise<void> {
+    error.value = null
+    try {
+      embedding.value = await reindexKbEmbeddings()
+      if (embedding.value.running && pollTimer === null) {
+        pollTimer = window.setInterval(() => void loadEmbedding(), POLL_INTERVAL_MS)
+      }
+    } catch (e) {
+      error.value = e instanceof Error ? e.message : '再埋め込みの開始に失敗しました'
+    }
+  }
+
   function toggleGroup(directory: string): void {
     const next = new Set(collapsed.value)
     if (next.has(directory)) next.delete(directory)
@@ -73,5 +143,25 @@ export const useKnowledgeBaseStore = defineStore('knowledgeBase', () => {
     collapsed.value = next
   }
 
-  return { files, openFile, loading, error, filter, collapsed, filteredFiles, groups, load, open, close, toggleGroup }
+  return {
+    files,
+    openFile,
+    loading,
+    error,
+    filter,
+    collapsed,
+    embedding,
+    probe,
+    testing,
+    filteredFiles,
+    groups,
+    load,
+    open,
+    close,
+    toggleGroup,
+    loadEmbedding,
+    stopPolling,
+    testEmbedding,
+    reindex,
+  }
 })