Add live hotspot network diagnostics

server/tests/app.test.ts

@@ -21,7 +21,8 @@ function testConfig(): AppConfig {
       enabled: false,
       statusPath: `/tmp/pi-car-companion-test-${process.pid}-missing-network-status.json`,
       commandPath: `/tmp/pi-car-companion-test-${process.pid}-network-command.json`,
-      configurationRequestPath: `/tmp/pi-car-companion-test-${process.pid}-network-configuration.json`
+      configurationRequestPath: `/tmp/pi-car-companion-test-${process.pid}-network-configuration.json`,
+      activityPath: `/tmp/pi-car-companion-test-${process.pid}-network-activity.json`
     },
     adb: { enabled: false, executable: "adb", serial: null, timeoutMs: 3_000 }
   };
@@ -189,6 +190,7 @@ describe("authentication boundary", () => {
   it("keeps network status and controls behind authentication and explicit configuration", async () => {
     const app = await createApp();
     expect((await app.inject({ method: "GET", url: "/api/network" })).statusCode).toBe(401);
+    expect((await app.inject({ method: "GET", url: "/api/network/activity" })).statusCode).toBe(401);
 
     const token = await csrf(app);
     await setup(app, token);
@@ -203,6 +205,9 @@ describe("authentication boundary", () => {
     const status = await app.inject({ method: "GET", url: "/api/network", headers: { cookie } });
     expect(status.statusCode).toBe(200);
     expect(status.json()).toMatchObject({ supported: false, enabled: false, mode: "disabled" });
+    const activity = await app.inject({ method: "GET", url: "/api/network/activity", headers: { cookie } });
+    expect(activity.statusCode).toBe(200);
+    expect(activity.json()).toMatchObject({ supported: false, clients: [], dnsQueries: [], flows: [] });
 
     const action = await app.inject({
       method: "POST",

server/tests/config.test.ts

@@ -27,7 +27,8 @@ describe("ADB configuration", () => {
       enabled: false,
       statusPath: "/var/lib/pi-car-companion/network-status.json",
       commandPath: "/var/lib/pi-car-companion/network-command.json",
-      configurationRequestPath: "/var/lib/pi-car-companion/network-configuration-request.json"
+      configurationRequestPath: "/var/lib/pi-car-companion/network-configuration-request.json",
+      activityPath: "/var/lib/pi-car-companion/network-activity.json"
     });
   });
 });

server/tests/network-activity.test.ts

@@ -0,0 +1,37 @@
+import { mkdtemp, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, describe, expect, it } from "vitest";
+import { readNetworkActivity } from "../src/network-activity.js";
+
+const directories: string[] = [];
+
+afterEach(async () => {
+  await Promise.all(directories.splice(0).map((directory) => rm(directory, { recursive: true, force: true })));
+});
+
+describe("network activity snapshot", () => {
+  it("accepts only bounded sanitized observer output", async () => {
+    const directory = await mkdtemp(join(tmpdir(), "pi-car-activity-test-"));
+    directories.push(directory);
+    const path = join(directory, "activity.json");
+    await writeFile(path, JSON.stringify({
+      collectedAt: "2026-07-31T20:00:00.000Z",
+      clients: [{ ipAddress: "10.42.0.20", macAddress: "aa:bb:cc:dd:ee:ff", hostname: "head-unit", leaseExpiresAt: null, state: "REACHABLE", connected: true }],
+      dnsQueries: [{ timestamp: "2026-07-31T20:00:00.000Z", clientAddress: "10.42.0.20", type: "A", name: "example.com" }],
+      flows: [{ protocol: "tcp", state: "ESTABLISHED", sourceAddress: "10.42.0.20", sourcePort: 50000, destinationAddress: "1.1.1.1", destinationPort: 443, packets: 4, bytes: 1000 }],
+      dnsAvailable: true,
+      flowsAvailable: true,
+      messages: []
+    }));
+    await expect(readNetworkActivity(path)).resolves.toMatchObject({ supported: true, clients: [{ hostname: "head-unit" }] });
+  });
+
+  it("does not expose malformed observer files", async () => {
+    const directory = await mkdtemp(join(tmpdir(), "pi-car-activity-test-"));
+    directories.push(directory);
+    const path = join(directory, "activity.json");
+    await writeFile(path, '{"clients":"not-an-array"}');
+    await expect(readNetworkActivity(path)).resolves.toMatchObject({ supported: false, clients: [] });
+  });
+});

server/tests/network.test.ts

@@ -29,7 +29,8 @@ function config(directory: string, enabled = true): AppConfig {
       enabled,
       statusPath: join(directory, "status.json"),
       commandPath: join(directory, "command.json"),
-      configurationRequestPath: join(directory, "configuration.json")
+      configurationRequestPath: join(directory, "configuration.json"),
+      activityPath: join(directory, "activity.json")
     },
     adb: { enabled: false, executable: "adb", serial: null, timeoutMs: 3_000 }
   };

server/tests/update.test.ts

@@ -22,7 +22,8 @@ function config(updateStatusPath: string, versionFile: string): AppConfig {
       enabled: false,
       statusPath: join(tmpdir(), "missing-network-status.json"),
       commandPath: join(tmpdir(), "network-command.json"),
-      configurationRequestPath: join(tmpdir(), "network-configuration.json")
+      configurationRequestPath: join(tmpdir(), "network-configuration.json"),
+      activityPath: join(tmpdir(), "network-activity.json")
     },
     adb: { enabled: false, executable: "adb", serial: null, timeoutMs: 3_000 }
   };