Upgrade to buttplug v5, add battery level display, bump to 0.2.0

buttplug-wasm@3.0.0 still declares buttplug@^4.0.2 as its dependency,
and v5 changed the OutputCmd wire shape (Value: number[] -> number) -
a real protocol difference, not just a type mismatch. Confirmed by
testing against real Lovense hardware that device control still works
in practice, so the bump stands; the risk is documented at the
client.connect() cast in case a future device/build doesn't fare as
well.

Also fixes a Map vs ReadonlyMap mismatch in the version-agnostic
feature-type extraction (v4 returns Map, v5 returns ReadonlyMap) that
surfaced while making this change, and adds a battery indicator to each
connected device's card - reads once on connect, refreshes every 60s,
using device.hasInput("Battery") to detect support.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W8WkFF5ppURBAB918593Eb

lib/buttplug/client.ts

@@ -1,4 +1,4 @@
-import type { ButtplugClient, ButtplugClientDevice } from "buttplug";
+import type { ButtplugClient, ButtplugClientDevice, InputType } from "buttplug";
 import { deriveActuators, type ButtplugRuntime } from "./commands";
 import { useButtplugStore } from "./store";
 import type { ConnectedDeviceInfo } from "./types";
@@ -20,6 +20,9 @@ function toDeviceInfo(device: ButtplugClientDevice): ConnectedDeviceInfo {
     name: device.name,
     displayName: device.displayName,
     actuators: deriveActuators(device),
+    // "Battery" is a string enum value - passing the literal avoids needing
+    // InputType as a runtime import here (see commands.ts for the same trick).
+    hasBattery: device.hasInput("Battery" as InputType),
   };
 }
 
@@ -45,7 +48,14 @@ async function initClient(): Promise<ClientHandle> {
   });
 
   const connector = new ButtplugWasmClientConnector();
-  await client.connect(connector);
+  // EXPERIMENTAL: buttplug-wasm@3.0.0's embedded server was built against
+  // buttplug@^4.0.2's wire format; buttplug@5's OutputCmd message shape
+  // changed (`Value` went from number[] to a bare number), which is a real
+  // protocol break, not just a type mismatch - the cast below silences that
+  // signal rather than fixing it. Scanning/pairing may still work since
+  // DeviceAdded's shape didn't change; device *commands* may be silently
+  // rejected or mis-parsed server-side. Revert to buttplug@^4.0.2 if so.
+  await client.connect(connector as unknown as Parameters<typeof client.connect>[0]);
 
   useButtplugStore.getState().setConnected(true);
   for (const device of client.devices.values()) {
@@ -94,3 +104,14 @@ export async function getDevice(deviceIndex: number): Promise<ButtplugClientDevi
   const { client } = await getButtplugClientHandle();
   return client.devices.get(deviceIndex);
 }
+
+/** Reads the current battery level (0-1), or null if unsupported/unreadable. */
+export async function getBatteryLevel(deviceIndex: number): Promise<number | null> {
+  const device = await getDevice(deviceIndex);
+  if (!device || !device.hasInput("Battery" as InputType)) return null;
+  try {
+    return await device.battery();
+  } catch {
+    return null;
+  }
+}