Auto-detect RGB565 endianness for RAW images to fix corrupted display

[Inter-Raptor]

Motivation

• Some RAW assets are produced with different RGB565 byte orders which caused strongly corrupted/noisy rendering when a fixed byte order was assumed.
• The launcher must reliably display icon.raw/title.raw/boot/background RAW files without manual re-conversion.

Description

• Added RawByteOrder utilities and a readRawPixelFromBytes() helper to decode 16-bit RGB565 pixels in either endianness in display_manager.cpp.
• Implemented detectRawByteOrder() which samples a few rows and chooses between RGB565_LE and RGB565_BE by computing a local smoothness score.
• Updated displayDrawRAW() to call the detector, decode pixels according to the detected order, and log the detected format to the serial console.

Testing

• Ran automated repository inspections including rg searches for RAW-related usages and file occurrences which completed successfully.
• Display file contents were examined with sed -n and nl -ba to verify the new functions and the updated displayDrawRAW() loop.
• Performed a diff review of the modified display_manager.cpp to confirm the expected changes were applied.
• No embedded build/flash was executed in this environment, so runtime validation on hardware remains to be performed (serial logs added to help runtime verification).

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Codex Task