feat(search): add @tower/search package with Meilisearch client and helpers

Implements Task 2 of Plan 4 (Archive & Search): provides createMeiliClient,
configureIndex, indexMessage, and deleteMessage for use by the worker and API.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/search/src/index.test.ts

@@ -0,0 +1,66 @@
+import {
+  MESSAGES_INDEX,
+  configureIndex,
+  indexMessage,
+  deleteMessage,
+  MeiliDocument,
+} from './index';
+
+function makeMockClient() {
+  const mockUpdateSettings = jest.fn().mockResolvedValue({});
+  const mockAddDocuments = jest.fn().mockResolvedValue({});
+  const mockDeleteDocument = jest.fn().mockResolvedValue({});
+  const mockIndex = jest.fn().mockReturnValue({
+    updateSettings: mockUpdateSettings,
+    addDocuments: mockAddDocuments,
+    deleteDocument: mockDeleteDocument,
+  });
+  return { client: { index: mockIndex } as any, mockIndex, mockUpdateSettings, mockAddDocuments, mockDeleteDocument };
+}
+
+describe('MESSAGES_INDEX', () => {
+  it('is the string tower-messages', () => {
+    expect(MESSAGES_INDEX).toBe('tower-messages');
+  });
+});
+
+describe('configureIndex', () => {
+  it('sets searchable, filterable, and sortable attributes on the correct index', async () => {
+    const { client, mockIndex, mockUpdateSettings } = makeMockClient();
+    await configureIndex(client);
+    expect(mockIndex).toHaveBeenCalledWith('tower-messages');
+    expect(mockUpdateSettings).toHaveBeenCalledWith({
+      searchableAttributes: ['content', 'senderName', 'sourceGroupName'],
+      filterableAttributes: ['sourceGroupId', 'tags', 'platform'],
+      sortableAttributes: ['approvedAt'],
+    });
+  });
+});
+
+describe('indexMessage', () => {
+  it('adds the document to the messages index', async () => {
+    const { client, mockIndex, mockAddDocuments } = makeMockClient();
+    const doc: MeiliDocument = {
+      id: 'msg-1',
+      content: 'Hello community',
+      senderName: 'Alice',
+      sourceGroupId: 'grp-1',
+      sourceGroupName: 'UP Parivar',
+      tags: ['#important'],
+      platform: 'whatsapp',
+      approvedAt: 1716825600000,
+    };
+    await indexMessage(client, doc);
+    expect(mockIndex).toHaveBeenCalledWith('tower-messages');
+    expect(mockAddDocuments).toHaveBeenCalledWith([doc]);
+  });
+});
+
+describe('deleteMessage', () => {
+  it('deletes document by id from the messages index', async () => {
+    const { client, mockIndex, mockDeleteDocument } = makeMockClient();
+    await deleteMessage(client, 'msg-1');
+    expect(mockIndex).toHaveBeenCalledWith('tower-messages');
+    expect(mockDeleteDocument).toHaveBeenCalledWith('msg-1');
+  });
+});

packages/search/src/index.ts

@@ -0,0 +1,36 @@
+import { MeiliSearch } from 'meilisearch';
+
+export { MeiliSearch } from 'meilisearch';
+
+export interface MeiliDocument {
+  id: string;              // DB Message.id
+  content: string;
+  senderName: string;      // empty string when null
+  sourceGroupId: string;
+  sourceGroupName: string;
+  tags: string[];
+  platform: string;
+  approvedAt: number;      // Unix ms — Meilisearch sorts numbers, not ISO strings
+}
+
+export const MESSAGES_INDEX = 'tower-messages';
+
+export function createMeiliClient(url: string, masterKey: string): MeiliSearch {
+  return new MeiliSearch({ host: url, apiKey: masterKey });
+}
+
+export async function configureIndex(client: MeiliSearch): Promise<void> {
+  await client.index(MESSAGES_INDEX).updateSettings({
+    searchableAttributes: ['content', 'senderName', 'sourceGroupName'],
+    filterableAttributes: ['sourceGroupId', 'tags', 'platform'],
+    sortableAttributes: ['approvedAt'],
+  });
+}
+
+export async function indexMessage(client: MeiliSearch, doc: MeiliDocument): Promise<void> {
+  await client.index(MESSAGES_INDEX).addDocuments([doc]);
+}
+
+export async function deleteMessage(client: MeiliSearch, id: string): Promise<void> {
+  await client.index(MESSAGES_INDEX).deleteDocument(id);
+}