v0.1.0 — the first cut, published to npm by hand

On npm. Published from the v0.1.0 tag by hand, the one version that
did not come from CI. CI at the tag passed every test and all six
templates; the only failure was a stale generated llms-full.txt.

The first complete cut of sheetpane, 17 packages at one version:

• <sheetpane-excel> and <sheetpane-errors> (@sheetpane/grid): open,
  edit and review .xlsx and .csv in the page. The sheet and its error
  list stay in sync through one in-memory workbook. Download hands back the
  original file with only your changes written in.
• Review: column rules, a JSON rules file and the workbook's own
  validation, with errors flagged on cells and listed beside the sheet.
• Editing basics: range selection, copy and paste, undo and redo, find,
  zoom, freeze panes, resize, and hidden rows, columns and sheets, with a
  dark theme.
• Nine plugins: numfmt, formulas, styles, validation, condfmt,
  images, charts, comments, visibility.
• For hosts and agents: @sheetpane/testing, @sheetpane/fixtures,
  @sheetpane/skills and @sheetpane/mcp; typings for React, Vue, Svelte
  and Solid; the custom-elements manifest.
• Requirements: browsers with DecompressionStream; Node 20+ for
  imports in Node (0.2.0 raises this to 22+). MIT licence.

Changed in detail

• Hidden rows, columns and sheets are honoured and marked (W-49): the
  grid no longer draws what the file hides as ordinary rows and tabs. A
  ◂▸ / ▴▾ marker shows each hidden span (with its errors), Show hidden and
  a marker click show it for viewing, hidden sheets are listed by a
  ⊘ n hidden button, outline groups get a gutter with +/− and levels, and
  an error in a hidden place is shown when selected. Keys, copy, Delete and
  totals skip hidden cells. Deprecated: ImportedSheet.hidden — use
  state (visible · hidden · veryHidden).

• Resize columns and rows (W-47): drag a header edge (a guide and the
  size while you drag), double-click to fit the text, several selected at
  once, or right-click a header for Fit · width… · Reset. Rows keep the
  file's custom heights and wrapped text wraps in them. Sizes are a view
  setting — not a change, not in the download — with sizes and
  sheetpane-resize for a host to keep them.

• Range selection is smooth and does more (W-46). The selection is one
  layer — a fill, one border, the active cell left clear — so a drag no longer
  redraws the cells (on 250,000 rows: no dropped frame dragging with
  autoscroll). Drag past an edge to scroll; click column or row headers or
  the corner; Ctrl/⌘+arrows, Ctrl+Space, Shift+Space, Ctrl/⌘+A,
  Shift+Backspace; Enter / Tab inside a range. A range copies as a grid
  (TSV + HTML), clears with Delete, fills from one pasted value, and shows
  Count · Sum · Average. sheetpane-select gains range and fires once per
  drag, on release. Touch: two handles. Removed: the cells' internal
  .inrange / .sel classes (in the shadow root, never host-facing).

• <sheetpane-excel>: one Download button (W-31). "Download .xlsx" /
  "Download .csv", in View and Edit, replaces Export and Download the
  original: with no change it hands back the file as opened, byte for
  byte; with changes it downloads export()'s copy, the change count on the
  button. sheetpane-export keeps its name and gains original: true for
  the untouched file. Removed: the separate download-original button.

• The selection bar no longer floats over the cells (W-31). Flag issue,
  the selbar plugin buttons and ⋯ (Copy ref, Copy value) are docked at the
  right end of the cell bar; right-click, Shift+F10 or the Menu key opens
  the same actions under the cell. The selbar slot keeps its id.

• Download is a neutral split button (W-34), not the accent colour: the
  main part downloads in the upload's format; ▾ offers Download as .xlsx
  or .csv (converting: one sheet, latest values) and each plugin's export
  options (comments: "Write review as Excel comments"). sheetpane-export
  gains format and converted.

Added in detail

• @sheetpane/visibility (W-49): hide and unhide rows, columns and
  sheets, and group outlines, in Edit — the selection bar, the cell, header
  and tab menus, Google Sheets' keys, a marker click — written into the
  download (patchXlsx's new hidden option). sheetpane-visibility event;
  store.setHidden, setSheetState, setOutline.

• custom-elements.json and typings (W-37): @sheetpane/grid ships the
  Custom Elements Manifest, VS Code and JetBrains editor data, and type-only
  entries @sheetpane/grid/jsx, /vue, /svelte, /solid — no host writes
  its own element typings. Angular: CUSTOM_ELEMENTS_SCHEMA (README).

• @sheetpane/mcp (W-39): npx -y @sheetpane/mcp — an MCP server
  (2026-07-28, stateless; 2025 clients too) with deterministic, read-only
  tools: inspect a workbook, draft and check a rules file, explain an SP
  code, find a skill, describe the API. sheetpane-skills install registers
  it for Claude Code, Kiro and Codex (--no-mcp to skip). Codes SP-7001…7007.

• @sheetpane/import reads .xlsx in Node (W-39): a built-in XML reader
  stands in when DOMParser is absent. Removed: the needs-dom refusal
  (SP-1008, retired). @sheetpane/testing's readFile uses it everywhere
  and drops its own Node reader and its @sheetpane/export dependency.

• TSDoc on the whole public API (W-36): every export's .d.ts carries a
  summary, parameters, returns, the elements' attributes and events, an example
  and a link to its record.

• llms.txt / llms-full.txt (W-38): sheetpane's public contract for AI
  agents, at the repository root and in @sheetpane/grid (dist/).

• @sheetpane/testing (W-41): sheetpane(page) for Playwright and
  sheetpane(element) for Vitest browser mode — edit, flag, resolve, Download
  read back, toHaveCell / toHaveError — on committed data-sp-* hooks.

• Agent skills (W-35): npx sheetpane-skills install copies 23 skills for
  Claude Code, Kiro and Codex into a repository, plus a short block in
  CLAUDE.md / AGENTS.md; uninstall removes exactly what it wrote.

• Stable error codes (W-40): every thrown error, console warning, rules
  note, refused load and blocked edit carries an SP-xxxx code with an entry
  in docs/ERRORS.md; spCode / codeOf() read it. Messages keep their old
  text after the code.

• A rules file (W-33): rules-src="./sheetpane.rules.json" or
  excel.rules = object — rules per sheet ("*" for all), by column title
  and by cell or range, with equals, noneOf and note; a JSON Schema
  ships as @sheetpane/grid/rules.schema.json. flagging="off" hides
  Flag issue and every pop-up: errors are read in the panel.

• Dark theme: theme="light" | "dark" | "auto" on both elements (W-29).

• Column rules by title — columns, validate, onInvalid (W-27).

• Plugins: @sheetpane/numfmt, formulas, styles, validation,
  condfmt, images, charts, comments (W-15–W-22).

• React hook recipes in examples/react (W-28).

• A plugin gallery in both demos: Vanilla, a tab per plugin and All plugins on
  one showcase workbook (W-32).