Problem

ExtendedResolution can produce the extra decimal digit in the wrong direction on some meters (different wheel rotation direction).

What this PR changes

• Adds a new per-number postprocessing option: ExtendedResolutionInvert (default: false)
• Parses config key EXTENDEDRESOLUTIONINVERT / main.ExtendedResolutionInvert
• Threads the flag into readout logic
• Inverts only the derived fractional digit when enabled
• Adds unit tests for normal vs inverted behavior
• Adds parameter docs for NUMBER.ExtendedResolutionInvert

Why this is safe

• Default is false, so existing behavior is unchanged unless user enables it.

Testing

• pio test -e esp32cam --without-uploading --without-testing ✅ (build/test compile pass)
• Hardware runtime test requires attached ESP32-CAM board (not available in this environment)

Usage

Set in config.ini when needed:

• main.ExtendedResolution = true
• main.ExtendedResolutionInvert = true (only for meters with opposite intermediate direction)