Problem
Tables in Docs have no real header row. The best you can do is make the first row bold with a grey background, and it scrolls away like any other row. With long, wide tables (evidence matrices, test logs, cause/effect tables) you lose track of which column is which after a few rows, so you keep scrolling back up or have to split one table into many.
Requested feature
  1. Mark rows as header rows:
    a "Set as header row" option in the row menu, for one or more top rows.
  2. Sticky on scroll:
    header rows stay pinned at the top of the viewport while you scroll through that table, and release when the table ends.
  3. Optional header column:
    pin the first column the same way for wide tables that scroll horizontally.
  4. Keep the semantics everywhere:
    header rows survive copy/paste, export (PDF, Markdown, HTML as
    <th>
    ) and import from Excel / Google Sheets when the source has a header row.
Why it matters
*
Readability:
engineering, QA and research teams use Docs tables as living reports. A 15+ row matrix with 4 or more text-heavy columns is hard to read without a fixed header.
*
Consistency:
Table view already has fixed headers and pinned columns, so users expect the same in Docs.
*
Fewer workarounds:
today people split one logical table into many small ones, which hurts structure and makes it harder to keep the data consistent.
Acceptance criteria
* Toggle header rows per table from the row options menu.
* Header stays visible while any part of the table body is on screen.
* Works in Docs, wikis and task descriptions, in light and dark mode.
* Exported files carry the header marking.