feat(eq): name Bluetooth devices from the system pairing list

A Bluetooth device only reports its own name through
AudioDeviceInfo.productName while it is enumerated as an active output, i.e.
while it is connected. Paired-but-switched-off devices therefore had no name
to fall back on, and the platform-name cache is in-memory only by design
(bt-device-identity ADR-4), so it self-heals per session ONLY for whatever
happens to be connected. Every other device showed its raw id.

Android already knows those names: BluetoothAdapter.getBondedDevices() lists
every pairing with its name and MAC, connected or not, and nothing in this
app was asking. Read it and seed the platform-name cache from it, keyed
bt_a2dp:<uppercase MAC> to match the ids the audio layer emits.

Seeded BEFORE the active-device query so a live enumeration name, being the
fresher of the two, still wins; a user's custom name outranks both. Re-read
on refrescarDispositivoActual so pairing or renaming a device in system
settings shows up as soon as the list becomes visible.

Reading the bond list is gated by BLUETOOTH_CONNECT from API 31 and by the
legacy BLUETOOTH permission below it, so declare the latter with
maxSdkVersion 30. It is a normal permission: granted at install, no runtime
prompt, no new friction. When the answer is unavailable — permission denied,
no adapter, Bluetooth off — both layers return an empty map rather than
throwing, and the row degrades to the id exactly as before.

Does not help rows persisted under a bt_a2dp:name: placeholder id: those
never had a MAC to match against.

android/app/src/main/AndroidManifest.xml

@@ -15,6 +15,14 @@
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT"/>
+    <!--
+        Reading the paired-device list is gated by BLUETOOTH_CONNECT from API 31
+        and by this legacy permission below it. Normal permission: granted at
+        install, no runtime prompt.
+    -->
+    <uses-permission
+        android:name="android.permission.BLUETOOTH"
+        android:maxSdkVersion="30"/>
 
     <application
         android:label="PluriWave"