feat(spreadsheet): write a cell of several runs

[andiwand]

🤖 Generated with Claude Code

Rebased on main now that #869 has landed. Step 2.3 of docs/design/spreadsheet-editing.md, and the last of step 2.

What it does

A cell whose paragraph held several runs was locked rich, because the write went through one text run and would have lost the others. What it loses is the formatting of a text the user is replacing anyway, which is what every spreadsheet does.

text_run_of descends through a single span before it looks for the run, so a cell that holds one run writes through it and that run keeps its style — the same walk spreadsheet.js::runOf makes over the page, which is what keeps the two showing the same thing. Where the paragraph holds several runs they are replaced by one, and the elements over the old children keep their ids and stop being reachable, as the xlsx write already did.

The rich lock stays on what a write would take away without the user seeing it go: a link, whose target is not what the cell shows, and a line break or several paragraphs, which are a second line the overlay cannot write.

xlsx needed no engine change — sheet_set_cell rewrites the whole c — so the lock alone changes there.

One thing worth knowing

Rebuilding a paragraph removes its old children from the dom while their elements keep their ids. Those elements' pugi::xml_node dangles from then on, which is the cost ooxml/spreadsheet already pays for the same tombstoning, and it is now written down in odf/AGENTS.md. Nothing reaches them through the tree; an Element handle taken before the write would.

Reference output

The pins are not advanced in this pull request. 1876 cells over 37 files lose data-odr-lock="rich" and its odr-locked class; every changed line in a local regeneration is one of those <td>s and nothing else. CI is green either way, because .odr-locked only sets a cursor and only under .odr-editing, so no pixel moves. The regeneration goes with the merge.

Test

OdfSheetWrite gains four cases: several runs written, one span kept, and a link and a line break that still refuse. OoxmlSpreadsheetWrite gains the rich inlineStr cell. html_test gains the cell of several runs that carries no lock and the link that is locked rich.

test/browser/sheet/editing.html held its rich cell as two runs; it holds a link now. All four sheet check pages pass in headless Chrome — 51, 14, 20 and 8 checks, none failed.

https://claude.ai/code/session_01KKFKbUVCYF2VhujdmjhhPW