[Enhancement] Replace static PNG screenshots with semantic HTML tables in write/fill docs

[nkuprins]

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Motivation

I was fixing the missing English localisation and noticed that static images were used for visual examples.

They are helpful, but using static images introduces several usability drawbacks:

1. Localization: hardcoded image text makes localization/i18n harder to maintain and to scale.
2. Style inconsistency: some other contributor may have a different app to open files with different colours/fonts

Solution

HTML tables styled to look like the spreadsheet, sharing one stylesheet so every doc page renders the same,
and delete the replaced PNGs.

While rewriting them, it became clear the text often relied on the screenshot alone, so the affected pages also get the missing explanations (fill placeholder syntax, header merge strategies, includeColumnFieldNames ordering, index gaps).

Alternatives

No response

Anything else?

No response

Are you willing to submit a PR?

• I'm willing to submit a PR!