Add built-in Lucide icon library for node styling

[jkemmererupgrade]

Description

Adds the Lucide icon library as a built-in source for node icons, introducing a searchable picker in the Node Styling panel alongside the existing custom-upload button.

Key architectural decision (per #1774): icon selections are stored as symbolic lucide:<name> references rather than data URIs. Resolution to a renderable form happens at render time, keeping config and export files human-readable and allowing the picker to highlight the current selection without reverse-engineering a blob.

Resolution at render time uses two paths depending on the consumer:

• React components (VertexIcon) — a new useResolvedIconUrl hook backed by React Query (staleTime: Infinity) converts lucide:<name> to a base64 SVG data URI on first use and caches the result per session. Plain URLs and data: URIs pass through via initialData, so they render immediately without an async round-trip.
• Cytoscape canvas (renderNode) — getLucideSvgString resolves the icon directly from the lucide-react dynamic-import map, skipping any network fetch.

Custom-uploaded icons (data: URIs) are completely unaffected — both resolvers pass them through unchanged.

The IconPicker component renders a searchable popover (8-column icon grid, 50-icon default window, type-to-filter). It emits the symbolic lucide:<name> ref so NodeStyleDialog stores the portable reference.

This commit also fixes a pre-existing lint-staged misconfiguration where the root oxlint --fix task matched vitest.config.ts, which oxlint then silently ignored (per its own ignorePatterns), causing a spurious exit-code 1 on pre-commit. The root lint-staged config now mirrors the oxlint ignore patterns.

This is Slice 1 of the 3-slice split of #1589, per @kmcginnes review.

Validation

All four local gates pass:

• pnpm run checks — oxlint, oxfmt, and TypeScript type-check all clean
• pnpm test — 1738 / 1738 tests pass (45 new tests across 4 new test files)
• pnpm coverage — all thresholds met; new files have ~100% line coverage (branches floor bumped 44 to 45 by the new branch coverage)
• pnpm build — production build completes without warnings

To validate the picker manually: open the Node Styling panel for any vertex type, click "Browse", search for an icon name (e.g. "plane"), select it, and confirm the node label updates in the graph view. Re-opening the dialog should show the selected icon highlighted in the grid.

Related Issues

Addresses #1774
Slice 1 of #1589

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I have verified pnpm checks passes with no errors.
• I have verified pnpm test passes with no failures.
• I have covered new added functionality with unit tests if necessary.
• I have updated documentation if necessary. (docs/features/graph-view.md)