Upgrade AG Grid and enhance the data viewer

[renkun-ken]

Upgrade AG Grid Community from 35.2.1 to 36.2.0 and add shared controls to the on-demand and file-backed data viewers. Columns fill the viewport by default and remain fitted through scrolling, page changes, and webview resizing; content sizing runs only when requested.

Closes #1586.

Changes

• Add searchable column visibility and pinning controls, floating filters, clear-all filters, row counts, and full-value tooltips. Showing or hiding floating filters preserves the current column order.
• Preserve compatible column layouts, sorting, filters, page sizes, and sizing modes across repeated View() calls. Reset restores fit-width sizing, and older saved fixed widths migrate to the new default.
• Replace outdated grid/selection API usage and initialize file-backed grids after the document is ready. Share date, boolean, missing-value, and integer64 handling between viewer modes.
• Update TypeScript to AG Grid's supported minimum of 5.8.3 and declare the test suite's glob dependency with compatible types.
• Document the viewer controls and add regression tests for sizing, state restoration, schema changes, pagination, and column types.

Validation

• Production bundle, TypeScript compilation, and ESLint on changed TypeScript files pass.
• Full extension suite in VS Code 1.119.0: 141 tests pass.
• R data-viewer suite: 79 checks pass; native AG Grid date and bigint filter models also verified against R.
• Headless Chrome checks using all 53,940 ggplot2::diamonds rows in both viewer modes, including scrolling, new blocks/pages, widening/narrowing, mode switching, reset, manual widths, and saved-state migration. No browser errors or AG Grid validation warnings.
• Chrome checks confirm floating filters render, apply, hide, and restore while preserving column order, widths/flex, pinning, visibility, and sorting. Reset clears sorting and filters and restores the default layout in paged, unpaged, and file-backed viewers.

[Copilot]

Copilot review overview

🟡 Changes recommended

Three moderate issues remain in filter toggling, sizing preservation, and reset sorting.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 1

Open (1)

• Changing defaultColDef does not update existing floating filters · New

What changed in this PR

Upgrades AG Grid and enhances both data viewers with shared controls, state persistence, sizing, filtering, and improved type handling.

Changes:

• Adds column search, visibility/pinning, filters, tooltips, row counts, and sizing controls.
• Preserves compatible viewer state and migrates older sizing settings.
• Updates dependencies, documentation, changelog, and regression tests.

File	Summary
src/​test/​suite/​dataViewer.test.ts	Viewer regression tests
src/​session.ts	Integrates shared viewer functionality
src/​dataViewerColumnPanel.ts	Searchable visibility and pinning panel
src/​dataViewer.ts	Shared viewer behavior and controls
README.md	Documents viewer controls
package.json	Updates dependencies and TypeScript
package-lock.json	Locks upgraded packages
CHANGELOG.md	Records viewer changes

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[ThomasSoeiro]

closes #1586

[Fred-Wu]

• Preserve compatible column layouts, sorting, filters, page sizes, and sizing modes across repeated View() calls. Reset restores fit-width sizing, and older saved fixed widths migrate to the new default.

There is an edge case bug that the column row-name width may not be preserved after Size to content and filtering buttons are clicked and View() is called again.

[Fred-Wu]

Change column.flex = 0 to column.initialFlex = 0 should preserve the column width for the row-indicator/name column.

[renkun-ken]

Confirmed and fixed in e2033d5. I reproduced the case from your PR comment: Size to content → Filters → reopen changed the row-name width from 51px back to 100px. Switching to initialFlex = 0 prevents filter toggles from reintroducing flex: 0 into the resized column's saved state, so its chosen width is restored correctly.

I also made Reset view explicitly restore the row-name column's initial width, since AG Grid skips width restoration when the reset state contains flex: 0.

Chrome checks pass for numeric and long character row names, covering content sizing, manual widths, filter toggles/application, repeated reloads, Reset, and fit-width during scrolling/resizing in paged/unpaged on-demand and file-backed viewers. No browser errors or AG Grid validation warnings. All 10 viewer tests, TypeScript compilation, changed-file ESLint, and the production build pass.