feat(03-01): add searchMessages backend with LIKE query, IPC channel, preload bridge, and tests

- Add searchMessages method to AppDatabase with LIKE query, wildcard escaping, channel scoping, ORDER BY created_at DESC with limit
- Add searchMessages IPC channel and searchMessagesSchema to contracts.ts
- Register IPC handler in ipc-agent-coordination-handlers.ts with Zod validation
- Wire searchMessages through preload bridge
- Add 8 unit tests covering body/subject search, wildcard escaping, channel scoping, empty results, limit, and ordering

tests/unit/message-search.test.ts

@@ -0,0 +1,207 @@
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+import { mkdtemp, rm } from "node:fs/promises";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("electron", () => ({
+  safeStorage: {
+    isEncryptionAvailable: () => false,
+    getSelectedStorageBackend: () => "basic_text",
+    encryptString: (value: string) => Buffer.from(value, "utf8"),
+    decryptString: (value: Buffer) => value.toString("utf8"),
+  },
+}));
+
+import { AppDatabase } from "../../src/main/database";
+
+describe("AppDatabase.searchMessages", () => {
+  let tempDir: string;
+  let db: AppDatabase;
+  let companyId: string;
+  let agentA: string;
+  let agentB: string;
+
+  beforeEach(async () => {
+    tempDir = await mkdtemp(join(tmpdir(), "agentcompany-search-"));
+    db = new AppDatabase(tempDir);
+    db.init();
+
+    companyId = db.saveCompany({
+      name: "Search Test Corp",
+      description: "Company for testing message search",
+      status: "active",
+    });
+
+    agentA = db.saveAgent({
+      companyId,
+      name: "Agent Alpha",
+      role: "Engineer",
+      title: "Senior Engineer",
+      status: "active",
+      reportsTo: null,
+      connectorId: "claude_local",
+      workspaceId: null,
+      model: null,
+      capabilities: "coding",
+      budgetMonthlyUsd: 100,
+    });
+
+    agentB = db.saveAgent({
+      companyId,
+      name: "Agent Beta",
+      role: "Designer",
+      title: "Lead Designer",
+      status: "active",
+      reportsTo: null,
+      connectorId: "claude_local",
+      workspaceId: null,
+      model: null,
+      capabilities: "design",
+      budgetMonthlyUsd: 100,
+    });
+
+    // Seed messages across different channels
+    db.sendAgentMessage({
+      companyId,
+      fromAgentId: agentA,
+      toAgentId: agentB,
+      channel: "direct",
+      subject: "Database migration plan",
+      body: "We need to migrate the PostgreSQL tables to the new schema.",
+      priority: "normal",
+    });
+
+    db.sendAgentMessage({
+      companyId,
+      fromAgentId: agentB,
+      toAgentId: agentA,
+      channel: "direct",
+      subject: "Design review feedback",
+      body: "The button colors look great, but the migration banner needs work.",
+      priority: "normal",
+    });
+
+    db.sendAgentMessage({
+      companyId,
+      fromAgentId: agentA,
+      channel: "company",
+      subject: "Sprint retrospective",
+      body: "Team velocity improved by 20% this sprint.",
+      priority: "normal",
+    });
+
+    db.sendAgentMessage({
+      companyId,
+      fromAgentId: agentA,
+      channel: "department",
+      channelTargetId: "engineering",
+      subject: "Code review standards",
+      body: "All PRs must have at least two approvals before merging.",
+      priority: "urgent",
+    });
+
+    db.sendAgentMessage({
+      companyId,
+      fromAgentId: agentB,
+      channel: "department",
+      channelTargetId: "design",
+      subject: "Design system update",
+      body: "We updated the color tokens for dark mode compatibility.",
+      priority: "low",
+    });
+  });
+
+  afterEach(async () => {
+    db.close();
+    await rm(tempDir, { recursive: true, force: true });
+  });
+
+  it("returns messages where body contains the query string", () => {
+    const results = db.searchMessages(companyId, "velocity");
+    expect(results.length).toBe(1);
+    expect(results[0].companyId).toBe(companyId);
+    expect(results[0].body.toLowerCase()).toContain("velocity");
+  });
+
+  it("returns messages where subject contains the query string", () => {
+    const results = db.searchMessages(companyId, "retrospective");
+    expect(results.length).toBe(1);
+    expect(results[0].subject).toBe("Sprint retrospective");
+  });
+
+  it("escapes LIKE wildcards so % and _ match literally", () => {
+    // Insert a message with literal % and _ characters
+    db.sendAgentMessage({
+      companyId,
+      fromAgentId: agentA,
+      channel: "company",
+      subject: "Performance metrics",
+      body: "CPU usage was 95% and disk_io dropped significantly.",
+      priority: "normal",
+    });
+
+    // Search for the literal "95%"
+    const percentResults = db.searchMessages(companyId, "95%");
+    expect(percentResults.length).toBe(1);
+    expect(percentResults[0].body).toContain("95%");
+
+    // Search for the literal "disk_io"
+    const underscoreResults = db.searchMessages(companyId, "disk_io");
+    expect(underscoreResults.length).toBe(1);
+    expect(underscoreResults[0].body).toContain("disk_io");
+  });
+
+  it("scopes to a specific channel when channel param is provided", () => {
+    const results = db.searchMessages(companyId, "approvals", { channel: "department" });
+    expect(results.length).toBe(1);
+    expect(results[0].channel).toBe("department");
+    expect(results[0].body).toContain("approvals");
+  });
+
+  it("scopes to channelTargetId when provided alongside channel", () => {
+    const results = db.searchMessages(companyId, "updated", {
+      channel: "department",
+      channelTargetId: "design",
+    });
+    expect(results.length).toBe(1);
+    expect(results[0].channelTargetId).toBe("design");
+  });
+
+  it("returns empty array when no matches", () => {
+    const results = db.searchMessages(companyId, "xyznonexistentquery");
+    expect(results).toEqual([]);
+  });
+
+  it("respects the limit parameter (default 50)", () => {
+    // Insert 60 messages
+    for (let i = 0; i < 60; i++) {
+      db.sendAgentMessage({
+        companyId,
+        fromAgentId: agentA,
+        channel: "company",
+        subject: `Bulk message ${i}`,
+        body: `This is a flood test message number ${i}`,
+        priority: "normal",
+      });
+    }
+
+    // Default limit should be 50
+    const defaultResults = db.searchMessages(companyId, "flood test");
+    expect(defaultResults.length).toBe(50);
+
+    // Explicit limit of 10
+    const limitedResults = db.searchMessages(companyId, "flood test", { limit: 10 });
+    expect(limitedResults.length).toBe(10);
+  });
+
+  it("returns results ordered by created_at DESC (most recent first)", () => {
+    const results = db.searchMessages(companyId, "migration");
+    expect(results.length).toBeGreaterThanOrEqual(2);
+
+    for (let i = 1; i < results.length; i++) {
+      const prev = new Date(results[i - 1].createdAt).getTime();
+      const curr = new Date(results[i].createdAt).getTime();
+      expect(prev).toBeGreaterThanOrEqual(curr);
+    }
+  });
+});