AP_HAL_ESP32: enable flash scripting on StampFly

[muramura]

Summary

Enable ESP32 internal flash FAT filesystem support on M5StampFly and use it as the Lua scripting filesystem at /APM/scripts.

Classification & Testing (check all that apply and add your own)

• Checked by a human programmer
• Non-functional change
• No-binary change
• Infrastructure change (e.g. unit tests, helper scripts)
• Automated test(s) verify changes (e.g. unit test, autotest)
• Tested manually, description below (e.g. SITL)
• Tested on hardware
• Logs attached
• Logs available on request

Built and tested on M5StampFly / esp32s3m5stampfly.

Build:

• ./waf copter -j1
• ardupilot.bin size: 0x1de720
• App partition free space: 0x1218e0 bytes, 38%

Hardware test:

• Flashed the generated firmware to M5StampFly.
• Verified the ESP32 flash filesystem mounted at /APM.
• Verified MAVFTP access to /APM/scripts.
• Uploaded hello.lua.
• Confirmed Lua execution through repeated GCS messages: AP: StampFly Lua OK.

Description

This PR enables Lua scripting on the ESP32-S3 based M5StampFly board by adding an internal flash FAT filesystem partition and mounting it through the existing ESP32 filesystem backend.

Changes include:

• Add a 1MB FAT partition named apm to the ESP32-S3 partition table.
• Mount the internal flash FAT filesystem at /APM.
• Create /APM/scripts automatically during mount.
• Enable AP_FILESYSTEM_ESP32_ENABLED and AP_SCRIPTING_ENABLED for esp32s3m5stampfly.
• Set the StampFly scripting directory to /APM/scripts.
• Enable SCR_ENABLE by default for StampFly.
• Link the ESP-IDF wear_levelling component required by FAT-on-flash.
• Allow Lua script loading to accept uppercase .LUA filenames returned by FAT directory listings.