Release v4.5.0

#242 had been open since 2 September with a complete, browser-verified NumberInput, and #264 shipped a smaller implementation for the same issue without noticing it. That is the duplication this resolves: #242's implementation becomes the canonical one, with its commits intact, on top of what has since shipped in 4.3.0 and 4.4.0.

Closes #242.

Added

• onCommit reporting blur, enter, paste and step after the matching change (#175)
• required with native form semantics, with normalization withheld from submission until the controlled owner accepts it (#175)
• Step buttons, description and error parts, and ReactNode adornments that stay outside the parsed and submitted value (#175)
• A --cratis-number-input-* token contract in its own stylesheet (#175)
• Specification coverage for useGrouping, which had none: a year must render 2026 and not 2 026 (#271)

Fixed

• Keep a full-field paste change and its commit in one browser event transaction, so WebKit preserves onChange before onCommit (#175)
• The Storybook verifiers printed hardcoded story and autodocs counts in their summaries while asserting different ones, so a passing run could report a number that was not real. Both now derive the count from the built index (#175)

Removed

• The seven specifications from #264, as redundant — every case they covered is covered here, usually more thoroughly (#175)

Verification

Full Source CI: 1478 tests across 415 files, parts manifest at 56 components and 297 parts, lint, build, story typecheck, renderer contracts and package graph. Storybook index and the complete axe matrix: 4 isolated previews × 295 stories × light and dark = 2360 story/appearance/axe cases, zero exclusions.