t-watch: spiffs+littlefs partition, maps initial support

variants/lilygo_twatch_s3_plus/meck_twatch_16mb.csv

@@ -0,0 +1,21 @@
+# Meck -- LilyGo T-Watch S3 Plus 16 MB custom partition layout
+#
+# Single factory app slot (no OTA): the watch has no SD card and does not
+# define MECK_OTA_UPDATE, so no firmware-OTA path is compiled -- an OTA
+# app1 slot would only waste flash. Maps get a dedicated LittleFS partition;
+# the DataStore keeps its own SPIFFS partition.
+#
+# Both data partitions use the 'spiffs' subtype (the standard ESP32 data
+# subtype). The DataStore is mounted as SPIFFS via SPIFFS.begin() (first
+# spiffs-subtype partition by offset); maps is mounted as LittleFS by the
+# explicit "maps" label, so the mount type is chosen at mount time, not by
+# subtype.
+#
+# NOTE: flashing this shifts the layout and wipes the existing SPIFFS --
+# re-provision identity/contacts after flashing.
+#
+# Name,   Type, SubType,  Offset,    Size
+nvs,      data, nvs,      0x9000,    0x5000
+app0,     app,  factory,  0x10000,   0x200000
+spiffs,   data, spiffs,   0x210000,  0x400000
+maps,     data, spiffs,   0x610000,  0x9F0000

variants/lilygo_twatch_s3_plus/platformio.ini

@@ -6,6 +6,7 @@ board_build.flash_mode = qio
 board_build.f_flash = 80000000L
 board_build.arduino.memory_type = qio_opi
 board_upload.flash_size = 16MB
+board_build.partitions = variants/lilygo_twatch_s3_plus/meck_twatch_16mb.csv
 build_flags =
   ${esp32_base.build_flags}
   ${sensor_base.build_flags}