Bump firmware version to 0.12.0 (version lockstep)

Author: HamzaYslmn

src/espbridge/commands.h

@@ -10,8 +10,8 @@
 // above stays the hard compatibility gate; this one signals feature parity.
 // tests/test_contract_sync.py enforces the lockstep.
 #define FW_VERSION_MAJOR 0
-#define FW_VERSION_MINOR 11
-#define FW_VERSION_PATCH 6
+#define FW_VERSION_MINOR 12
+#define FW_VERSION_PATCH 0
 
 // Frame (logical, pre-COBS):
 //   flags u8 | seq u8 | cmd u16 BE | payload .. | crc16 BE