fix: align NIP-BE chunk format with KoalaSat/samiz reference implementation

Reviewed the samiz BLE implementation and fixed compatibility issues:

- Chunk index: changed from 2 bytes to 1 byte (matching samiz/NIP-BE example)
- Chunk overhead: 2 bytes total (1 index + 1 total count), not 3
- chunkSize parameter now means payload size (500), not total chunk size
- Android: TX power HIGH, advertise timeout indefinite (matching samiz)
- Android: request MTU 512 and CONNECTION_PRIORITY_HIGH on connect
- Android: discover services after MTU negotiation (samiz flow)
- Android: set WRITE_TYPE_DEFAULT on write characteristic
- MTU-to-chunkSize: properly accounts for ATT overhead (3) + chunk overhead (2)

These changes ensure wire-level compatibility with samiz devices.

https://claude.ai/code/session_01Tz5E73Rj7tL48A3qUGS5DT

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nipBEBle/BleMessageChunkerTest.kt

@@ -48,15 +48,19 @@ class BleMessageChunkerTest {
     @Test
     fun chunksHaveCorrectFormat() {
         val message = """["EVENT",{"id":"abc","kind":1,"content":"hello world"}]"""
-        val chunks = BleMessageChunker.splitIntoChunks(message, chunkSize = 20)
+        val chunkSize = 20
+        val chunks = BleMessageChunker.splitIntoChunks(message, chunkSize = chunkSize)
 
         for ((i, chunk) in chunks.withIndex()) {
-            // First 2 bytes are the index
+            // First byte is the index
             assertEquals(i, BleMessageChunker.chunkIndex(chunk))
             // Last byte is the total count
             assertEquals(chunks.size, BleMessageChunker.totalChunks(chunk))
-            // Each chunk should be at most chunkSize
-            assertTrue(chunk.size <= 20, "Chunk size ${chunk.size} exceeds max 20")
+            // Each chunk should be at most chunkSize + 2 (overhead)
+            assertTrue(
+                chunk.size <= chunkSize + BleMessageChunker.CHUNK_OVERHEAD,
+                "Chunk size ${chunk.size} exceeds max ${chunkSize + BleMessageChunker.CHUNK_OVERHEAD}",
+            )
         }
     }