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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "sexy",
-  "version": "0.1.1",
+  "version": "0.2.0",
   "private": true,
   "scripts": {
     "dev": "next dev",
@@ -12,7 +12,7 @@
   },
   "dependencies": {
     "better-sqlite3": "^13.0.3",
-    "buttplug": "^4.0.2",
+    "buttplug": "^5.0.1",
     "buttplug-wasm": "^3.0.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",