[kriboe90]

Follow-up to #185 for the README.

• Leaves out the sections on the analysed quantities and result files, on the reference images of the normalization, on the camera behind a window pane, on dense smoke and the read noise of the sensor (the unclipped intensities and the averaging of images) and on the features in validation.
• Shortens the section on the far-field pedestal to the option, what step 3 does, the two quantities it writes and the two limits: the check with farbg_pedestal / sum_col_val and the tests in dark rooms only.
• Adds doc/images/farfield_bands.svg. It shows the two bands beside a search area and how the zone around a neighbouring strip cuts one of them short. It has a light and a dark colour scheme that follow prefers-color-scheme, each on its own background, so it stays readable in both GitHub themes.

The README is also the description on PyPI, where a relative image path does not resolve, so it embeds the figure from master on raw.githubusercontent.com. The figure therefore shows in the README only after the merge. Preview from this branch:

🤖 Generated with Claude Code