feat: Maestro driver integration + DeviceDriver architecture (#32)

* proto(driver): drop launcher_activity from LaunchRequest

* refactor(driver): rename Driver to DeviceDriver, drop launcherActivity from Launch

* refactor(driver): rename package maestro to sidecar

* feat(driver): add ChromeDriver backed by chromedp

* feat(hierarchy): replace XML parser with TreeNode JSON parser

* refactor(driver): update mock and runner to DeviceDriver, drop launcherActivity

* feat(runner): add platform routing for web vs sidecar

* test(verifier): update hierarchy fixtures from XML to TreeNode JSON

* feat(sidecar): extract readLogcat/readProcMetrics; add MaestroDriverBackend

- Extract readLogcat() and readProcMetrics() as internal package-level
  helpers parameterised by serial
- Add MaestroDriverBackend wiring maestro-client AndroidDriver
- Drop launcherActivity from DriverBackend interface and StubDriverBackend
- Add maestro-utils and micrometer-core as explicit compile deps

* refactor(sidecar): inject DriverBackend into DriverService; drop launcherActivity

- Remove serial and default backend from DriverService constructor
- Make backend a required parameter
- Drop launcherActivity from launch RPC handler
- Create MaestroDriverBackend in Main.kt when platform is android

* test(sidecar): update tests for dropped launcherActivity and required backend

* chore(sidecar): remove unnecessary micrometer-core direct dependency

cmd/sanderling/main.go

@@ -15,14 +15,13 @@ import (
 var Version = "dev"
 
 type testOptions struct {
-	spec             string
-	bundleID         string
-	launcherActivity string
-	platform         string
-	avd              string
-	duration         time.Duration
-	seed             int64
-	output           string
+	spec     string
+	bundleID string
+	platform string
+	avd      string
+	duration time.Duration
+	seed     int64
+	output   string
 }
 
 const topUsage = `sanderling is a property-based UI fuzzer for mobile apps.
@@ -45,8 +44,7 @@ func parseTestArgs(args []string, stderr io.Writer) (testOptions, error) {
 	var options testOptions
 	flagSet.StringVar(&options.spec, "spec", "", "path to the TypeScript spec (required)")
 	flagSet.StringVar(&options.bundleID, "bundle-id", "", "target app bundle ID (required)")
-	flagSet.StringVar(&options.launcherActivity, "launcher-activity", "", "optional <pkg>/<activity> to launch (overrides default resolution)")
-	flagSet.StringVar(&options.platform, "platform", "android", "target platform: android (ios deferred)")
+	flagSet.StringVar(&options.platform, "platform", "android", "target platform: android, web")
 	flagSet.StringVar(&options.avd, "avd", "", "Android AVD name to boot if no device is connected")
 	flagSet.DurationVar(&options.duration, "duration", 5*time.Minute, "total test duration")
 	flagSet.Int64Var(&options.seed, "seed", 0, "RNG seed (0 = random)")
@@ -60,8 +58,10 @@ func parseTestArgs(args []string, stderr io.Writer) (testOptions, error) {
 	if options.bundleID == "" {
 		return testOptions{}, errors.New("--bundle-id is required")
 	}
-	if options.platform != "android" {
-		return testOptions{}, fmt.Errorf("unsupported platform: %q (only android in v0.1)", options.platform)
+	switch options.platform {
+	case "android", "ios", "web":
+	default:
+		return testOptions{}, fmt.Errorf("unsupported platform: %q (android, web)", options.platform)
 	}
 	return options, nil
 }