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

proto/driverpb/driver.pb.go

@@ -58,15 +58,11 @@ func (*Empty) Descriptor() ([]byte, []int) {
 }
 
 type LaunchRequest struct {
-	state      protoimpl.MessageState `protogen:"open.v1"`
-	BundleId   string                 `protobuf:"bytes,1,opt,name=bundle_id,json=bundleId,proto3" json:"bundle_id,omitempty"`
-	ClearState bool                   `protobuf:"varint,2,opt,name=clear_state,json=clearState,proto3" json:"clear_state,omitempty"`
-	// Optional "<pkg>/<activity>" component to pass to `am start -n`. Needed
-	// when an app declares multiple MAIN+LAUNCHER activities where the first
-	// one reported by `pm dump` is an alias whose target class is disabled.
-	LauncherActivity string `protobuf:"bytes,3,opt,name=launcher_activity,json=launcherActivity,proto3" json:"launcher_activity,omitempty"`
-	unknownFields    protoimpl.UnknownFields
-	sizeCache        protoimpl.SizeCache
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	BundleId      string                 `protobuf:"bytes,1,opt,name=bundle_id,json=bundleId,proto3" json:"bundle_id,omitempty"`
+	ClearState    bool                   `protobuf:"varint,2,opt,name=clear_state,json=clearState,proto3" json:"clear_state,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
 }
 
 func (x *LaunchRequest) Reset() {
@@ -113,13 +109,6 @@ func (x *LaunchRequest) GetClearState() bool {
 	return false
 }
 
-func (x *LaunchRequest) GetLauncherActivity() string {
-	if x != nil {
-		return x.LauncherActivity
-	}
-	return ""
-}
-
 type Point struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	X             int32                  `protobuf:"varint,1,opt,name=x,proto3" json:"x,omitempty"`
@@ -850,12 +839,11 @@ var File_driverpb_driver_proto protoreflect.FileDescriptor
 const file_driverpb_driver_proto_rawDesc = "" +
 	"\n" +
 	"\x15driverpb/driver.proto\x12\x14sanderling.driver.v1\"\a\n" +
-	"\x05Empty\"z\n" +
+	"\x05Empty\"M\n" +
 	"\rLaunchRequest\x12\x1b\n" +
 	"\tbundle_id\x18\x01 \x01(\tR\bbundleId\x12\x1f\n" +
 	"\vclear_state\x18\x02 \x01(\bR\n" +
-	"clearState\x12+\n" +
-	"\x11launcher_activity\x18\x03 \x01(\tR\x10launcherActivity\"#\n" +
+	"clearState\"#\n" +
 	"\x05Point\x12\f\n" +
 	"\x01x\x18\x01 \x01(\x05R\x01x\x12\f\n" +
 	"\x01y\x18\x02 \x01(\x05R\x01y\"\x1c\n" +

proto/driverpb/driver.proto

@@ -30,10 +30,6 @@ message Empty {}
 message LaunchRequest {
   string bundle_id = 1;
   bool clear_state = 2;
-  // Optional "<pkg>/<activity>" component to pass to `am start -n`. Needed
-  // when an app declares multiple MAIN+LAUNCHER activities where the first
-  // one reported by `pm dump` is an alias whose target class is disabled.
-  string launcher_activity = 3;
 }
 
 message Point {