Add ready probe to esp32_connect for reliable startup

The boot event fires early in app_main before the UART command
handler task is fully initialised. This means the first command
after connect can get lost, causing transient ping timeouts.

Now esp32_connect retries a ping (up to 5 attempts, 1s timeout
each) after the boot-event wait, so it only returns "connected"
when the firmware is actually responsive.

src/mcbluetooth_esp32/tools/connection.py

@@ -8,7 +8,7 @@ from typing import Any
 from fastmcp import FastMCP
 
 from ..protocol import CMD_GET_INFO, CMD_GET_STATUS, CMD_PING, CMD_RESET, Status
-from ..serial_client import NotConnected, get_client, init_client
+from ..serial_client import CommandTimeout, NotConnected, get_client, init_client
 
 
 def register_tools(mcp: FastMCP) -> None:
@@ -51,11 +51,25 @@ def register_tools(mcp: FastMCP) -> None:
         except TimeoutError:
             pass
 
+        # Ready probe: retry ping until the firmware's command handler is up.
+        # The boot event fires early in app_main, before the UART command
+        # task is fully initialised, so the first command can get lost.
+        ready = False
+        for attempt in range(5):
+            try:
+                resp = await client.send_command(CMD_PING, timeout=1.0)
+                if resp.status == Status.OK:
+                    ready = True
+                    break
+            except (CommandTimeout, NotConnected):
+                await asyncio.sleep(0.3)
+
         return {
             "connected": True,
             "port": port,
             "baudrate": baudrate,
             "boot_event": boot_received,
+            "ready": ready,
         }
 
     @mcp.tool()