feat: add semantic/RAG vault indexing with automatic background sync

- Add VaultVectorStore backed by ChromaDB for vector-based vault search
- Integrate existing ContentVectorizer/IndexingPipeline for embeddings
- Update VaultIndexer to prefer semantic search with keyword fallback
- Background indexing on plugin load + incremental sync via vault events
- Add vault index settings, commands, and UI controls
- Add tests for VaultVectorStore
- Update README with RAG setup instructions

src/chat-view.ts

@@ -1,6 +1,7 @@
 import { ItemView, Notice, WorkspaceLeaf } from 'obsidian';
 import { OllamaClient } from './ollama-client';
 import { VaultIndexer } from './vault-indexer';
+import { VaultVectorStore } from './vault-vector-store';
 import { ToolExecutor } from './tool-executor';
 import { PluginSettings, OllamaMessage, OllamaTool, OllamaToolCall, ChatMessage } from './types';
 import { ConversationStateManager } from './conversation-state';
@@ -22,7 +23,7 @@ export class ChatView extends ItemView {
     return this.newChatButtonClickHandler;
   }
 
-  constructor(leaf: WorkspaceLeaf, settings: PluginSettings) {
+  constructor(leaf: WorkspaceLeaf, settings: PluginSettings, vectorStore?: VaultVectorStore) {
     super(leaf);
     this.messages = [];
     this.lastMessageEl = null;
@@ -44,7 +45,7 @@ export class ChatView extends ItemView {
       undefined,
       settings.cacheConfig
     );
-    this.vaultIndexer = new VaultIndexer(this.app.vault);
+    this.vaultIndexer = new VaultIndexer(this.app.vault, undefined, vectorStore);
     this.toolExecutor = new ToolExecutor(this.app.vault, this.app);
     this.conversationStateManager = new ConversationStateManager();
   }
@@ -64,6 +65,11 @@ export class ChatView extends ItemView {
     });
   }
 
+  setVectorStore(vectorStore: VaultVectorStore | undefined) {
+    this.vectorStore = vectorStore;
+    this.vaultIndexer.setVectorStore(vectorStore);
+  }
+
   async clearCache(): Promise<void> {
     await this.ollamaClient.clearCache();
   }
@@ -567,6 +573,7 @@ export class ChatView extends ItemView {
   private vaultIndexer: VaultIndexer;
   private toolExecutor: ToolExecutor;
   private conversationStateManager: ConversationStateManager;
+  private vectorStore?: VaultVectorStore;
 }
 
 const MAX_TOOL_CALLS = 5;