Auto-detect upload port via ID? serial query (issue #11)

- Add ID? command to firmware: server responds 'SylDa_Server', client 'SylDa_Client'
- Add tools/pio_upload_port.py POST-script that queries connected ESP32s
- Remove hardcoded upload_port from platformio.ini
- Script logic: 1 ESP32 → use directly, 2+ → ID? query, no match → prompt user
- Requires pyserial for serial queries (graceful fallback if missing)

platformio.ini

@@ -11,11 +11,12 @@ build_flags =
 lib_deps =
     fastled/FastLED@^3
     h2zero/NimBLE-Arduino@^2
-upload_port = /dev/serial/by-id/usb-Espressif_USB_JTAG_serial_debug_unit_44:1B:F6:F4:CF:14-if00
 upload_speed = 115200
 upload_flags = --no-stub
 build_src_filter = +<main.cpp> -<client.cpp>
-extra_scripts = pre:tools/pio_version_pre.py
+extra_scripts =
+    pre:tools/pio_version_pre.py
+    post:tools/pio_upload_port.py
 
 [env:s3lite-client]
 platform = espressif32@6.7.0
@@ -31,8 +32,9 @@ build_flags =
 lib_deps =
     fastled/FastLED@^3
     h2zero/NimBLE-Arduino@^2
-upload_port = /dev/ttyACM2
 upload_speed = 115200
 upload_flags = --no-stub
 build_src_filter = +<client.cpp> -<main.cpp>
-extra_scripts = pre:tools/pio_version_pre.py
+extra_scripts =
+    pre:tools/pio_version_pre.py
+    post:tools/pio_upload_port.py