[jjbaumert]

Intent

Let authors keep live spreadsheet calculations inside ordinary document prose.

Closes #133.

What changed

Add editable, bounded grid blocks with raw formulas, number formats, multiple sheets, parent undo/redo and read-only controls. Extract the existing spreadsheet engine for browser/server reuse while preserving its frontend module paths and original test assertions.

Persist independent cell and format keys through Yrs. Keep active sheet, drafts and selection local; retain focused inputs across unrelated edits. Native snapshots preserve source, and HTML/Markdown/DOCX/PDF render computed tables. Schema validation and exports enforce documented size/evaluation limits.

How this was tested

• Real browser red/green: insertion, formula calculation, focusout persistence, rejected-draft ownership, focused-workbook undo, multiple sheets/workbooks, history, concurrent WebSocket edits, viewer permissions and reload.
• Actual persisted APIs after all clients close: HTML/Markdown/DOCX/PDF exports plus native download/upload into a separate document, preserving formulas, formats and identities.
• 386 shared-engine, 676 collab/export, 1195 frontend library, 459 frontend binary and 14 collaboration tests passed. A 9000-cell regression proves one edit emits less than 256 bytes and converges on a fresh peer.
• Strict shared/collab Clippy and new-module formatting pass. Full frontend Clippy retains 150 diagnostics on unchanged lines; none remain on changed lines. Broad pre-existing repository formatting drift remains.
• Playwright CI runs both new edge regressions and full acceptance. Its established browser build omits PDF to avoid cold-build timeouts, so that invocation explicitly skips PDF; default local acceptance and regular backend CI cover PDF.

Evidence is retained locally in .ship/evidence-inline-spreadsheet.log. Full Playwright run: https://github.com/jjbaumert/OgreNotes/actions/runs/40799382414

Findings fixed during review

Fix draft persistence on leaving a grid, rejected-draft navigation writing the wrong cell, and cursor restoration after removing a focused workbook. Restore merge predicate grouping, bound INDEX offsets, and implement advertised numeric patterns. Align CI export checks with its intentionally reduced feature set. Follow-up fresh-context reviews have no outstanding findings.

Risk: high

Adds persisted node types and collaborative editing behavior. Existing old browser tabs must be refreshed before editing documents with the new block types. Formula/evaluation limits and export differences are documented in crates/spreadsheet/README.md.