feat(gateway): add config hot reload

src/gateway/config-reload.test.ts

@@ -0,0 +1,63 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildGatewayReloadPlan,
+  diffConfigPaths,
+  resolveGatewayReloadSettings,
+} from "./config-reload.js";
+
+describe("diffConfigPaths", () => {
+  it("captures nested config changes", () => {
+    const prev = { hooks: { gmail: { account: "a" } } };
+    const next = { hooks: { gmail: { account: "b" } } };
+    const paths = diffConfigPaths(prev, next);
+    expect(paths).toContain("hooks.gmail.account");
+  });
+
+  it("captures array changes", () => {
+    const prev = { routing: { groupChat: { mentionPatterns: ["a"] } } };
+    const next = { routing: { groupChat: { mentionPatterns: ["b"] } } };
+    const paths = diffConfigPaths(prev, next);
+    expect(paths).toContain("routing.groupChat.mentionPatterns");
+  });
+});
+
+describe("buildGatewayReloadPlan", () => {
+  it("marks gateway changes as restart required", () => {
+    const plan = buildGatewayReloadPlan(["gateway.port"]);
+    expect(plan.restartGateway).toBe(true);
+    expect(plan.restartReasons).toContain("gateway.port");
+  });
+
+  it("restarts the Gmail watcher for hooks.gmail changes", () => {
+    const plan = buildGatewayReloadPlan(["hooks.gmail.account"]);
+    expect(plan.restartGateway).toBe(false);
+    expect(plan.restartGmailWatcher).toBe(true);
+    expect(plan.reloadHooks).toBe(true);
+  });
+
+  it("restarts providers for web/telegram changes", () => {
+    const plan = buildGatewayReloadPlan(["web.enabled", "telegram.botToken"]);
+    expect(plan.restartGateway).toBe(false);
+    expect(plan.restartProviders.has("whatsapp")).toBe(true);
+    expect(plan.restartProviders.has("telegram")).toBe(true);
+  });
+
+  it("treats gateway.remote as no-op", () => {
+    const plan = buildGatewayReloadPlan(["gateway.remote.url"]);
+    expect(plan.restartGateway).toBe(false);
+    expect(plan.noopPaths).toContain("gateway.remote.url");
+  });
+
+  it("defaults unknown paths to restart", () => {
+    const plan = buildGatewayReloadPlan(["unknownField"]);
+    expect(plan.restartGateway).toBe(true);
+  });
+});
+
+describe("resolveGatewayReloadSettings", () => {
+  it("uses defaults when unset", () => {
+    const settings = resolveGatewayReloadSettings({});
+    expect(settings.mode).toBe("hybrid");
+    expect(settings.debounceMs).toBe(300);
+  });
+});