feat: Switch to persistent Chroma HTTP server

Replace MCP subprocess approach with persistent Chroma HTTP server for
improved performance and reliability. This re-enables Chroma on Windows
by eliminating the subprocess spawning that caused console popups.

Changes:
- NEW: ChromaServerManager.ts - Manages local Chroma server lifecycle
  via `npx chroma run`
- REFACTOR: ChromaSync.ts - Uses chromadb npm package's ChromaClient
  instead of MCP subprocess (removes Windows disabling)
- UPDATE: worker-service.ts - Starts Chroma server on initialization
- UPDATE: GracefulShutdown.ts - Stops Chroma server on shutdown
- UPDATE: SettingsDefaultsManager.ts - New Chroma configuration options
- UPDATE: build-hooks.js - Mark optional chromadb deps as external

Benefits:
- Eliminates subprocess spawn latency on first query
- Single server process instead of per-operation subprocesses
- No Python/uvx dependency for local mode
- Re-enables Chroma vector search on Windows
- Future-ready for cloud-hosted Chroma (claude-mem pro)
- Cross-platform: Linux, macOS, Windows

Configuration:
  CLAUDE_MEM_CHROMA_MODE=local|remote
  CLAUDE_MEM_CHROMA_HOST=127.0.0.1
  CLAUDE_MEM_CHROMA_PORT=8000
  CLAUDE_MEM_CHROMA_SSL=false

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/services/worker-service.ts

@@ -14,6 +14,7 @@ import { Client } from '@modelcontextprotocol/sdk/client/index.js';
 import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
 import { getWorkerPort, getWorkerHost } from '../shared/worker-utils.js';
 import { logger } from '../utils/logger.js';
+import { ChromaServerManager } from './sync/ChromaServerManager.js';
 
 // Version injected at build time by esbuild define
 declare const __DEFAULT_PACKAGE_VERSION__: string;
@@ -120,6 +121,9 @@ export class WorkerService {
   // Route handlers
   private searchRoutes: SearchRoutes | null = null;
 
+  // Chroma server (local mode)
+  private chromaServer: ChromaServerManager | null = null;
+
   // Initialization tracking
   private initializationComplete: Promise<void>;
   private resolveInitialization!: () => void;
@@ -256,8 +260,33 @@ export class WorkerService {
       const { ModeManager } = await import('./domain/ModeManager.js');
       const { SettingsDefaultsManager } = await import('../shared/SettingsDefaultsManager.js');
       const { USER_SETTINGS_PATH } = await import('../shared/paths.js');
+      const os = await import('os');
 
       const settings = SettingsDefaultsManager.loadFromFile(USER_SETTINGS_PATH);
+
+      // Start Chroma server if in local mode
+      const chromaMode = settings.CLAUDE_MEM_CHROMA_MODE || 'local';
+      if (chromaMode === 'local') {
+        logger.info('SYSTEM', 'Starting local Chroma server...');
+        this.chromaServer = ChromaServerManager.getInstance({
+          dataDir: path.join(os.homedir(), '.claude-mem', 'vector-db'),
+          host: settings.CLAUDE_MEM_CHROMA_HOST || '127.0.0.1',
+          port: parseInt(settings.CLAUDE_MEM_CHROMA_PORT || '8000', 10)
+        });
+
+        await this.chromaServer.start();
+        const ready = await this.chromaServer.waitForReady(60000);
+
+        if (ready) {
+          logger.success('SYSTEM', 'Chroma server ready');
+        } else {
+          logger.warn('SYSTEM', 'Chroma server failed to start - vector search disabled');
+          this.chromaServer = null;
+        }
+      } else {
+        logger.info('SYSTEM', 'Chroma remote mode - skipping local server');
+      }
+
       const modeId = settings.CLAUDE_MEM_MODE;
       ModeManager.getInstance().loadMode(modeId);
       logger.info('SYSTEM', `Mode loaded: ${modeId}`);
@@ -430,7 +459,8 @@ export class WorkerService {
       server: this.server.getHttpServer(),
       sessionManager: this.sessionManager,
       mcpClient: this.mcpClient,
-      dbManager: this.dbManager
+      dbManager: this.dbManager,
+      chromaServer: this.chromaServer || undefined
     });
   }