feat: PresentationDeck engine + deck primitives with a behavioral eval suite

[theclaymethod]

Summary

A second deck engine for presented (not scrolled) decks, generalized from a production deck built with this pipeline — plus an eval suite that IS its behavioral contract.

• PresentationDeck / PresentationSlide (visual-explainer-mdx/presentation.tsx): fixed 1920×1080 stage scaled to fit via ResizeObserver (min(w/1920, h/1080), letterboxed on the new --ve-deck-letterbox token), collapsible slide rail (auto-collapse → dot column, hover expand, active indicator), keyboard nav (arrows/Space/PageUp/PageDown/Home/End), 80px edge click zones, mono slide counter, cubic-bezier(0.22,1,0.36,1) transitions.
• Drill-down primitives: DrillCard (corner-anchored expansion over neighbors via transform-origin), DrillChip (CTA discipline: primary = solid accent fill, secondary = outline), DrillSheet (Escape/X + click-anywhere-to-close guarded by closest('button, a, input, select, textarea, [data-interactive], [data-drill-target]')), LayerExplorer.
• Composition primitives: LadderDiagram/FanoutDiagram (grid paper with opaque solid-over-grid fills — the CSS equivalent of solidTint()), PullQuote, Metric/StatRow, HairlineList, Stepper, CodePanel, MonoLabel/DisplayText, IconChip + geometric icons, ShineOverlay/trackShine, hover-lift CSS.
• Zero brand values: everything consumes --ve-* tokens; slide tones reuse Slide's data-ve-tone → --ve-slide-* mapping, so all existing presets skin the deck untouched (independent of the design-system-registry PR). prefers-reduced-motion collapses all deck motion.
• Existing SlideDeck/Slide exports are untouched; the new components re-export through visual-explainer-mdx/components.tsx and the roster-sync guard now parses re-exports.

The eval suite is the spec

evals/run-presentation.mjs (npm run ve:eval-presentation, documented sibling of evals/run.mjs, wired into the CI evals job) exports the demo through the standard ve:export path and replays the contract headlessly — 18 evals:

Group	Evals
interaction	dismiss-guard matrix (each of button/a/input/select/textarea/[data-interactive] keeps the sheet open; passive prose closes it; Escape + X always close), keyboard-nav matrix with counter assertions incl. clamping, drill CTA contract (every trigger opens via click/Enter/Space; primary solid vs secondary outline computed styles), LayerExplorer selection, reduced-motion, no-console-errors
geometry	stage transform == fitStage() at 1440×900 / 1920×1080 / 1024×768 / 800×1000, letterbox on mismatched ratio, rail 260↔44px collapse/hover-expand + rail navigation, Metric no-wrap/no-overflow under the widest display font
tokens	second-preset export changes computed surface/CTA/font values; an allowlist-based literal scan: the shipped module must contain NO color literals (hex/rgb()/hsl()/oklch()/oklab()) and no concrete font-family at all — every visual value must arrive via a --ve-* token. The only allowlisted literals are two documented neutral var(..., fallback) values and one docstring example

Falsification check: each eval class was verified to fail by sabotaging the behavior and reverting — guard return true → dismiss-matrix failed; fitStage min→max → letterbox failed; a hardcoded CTA color → CTA-style, preset-reskin, and literal-scan evals failed.

Unit tests (npm test, in CI): scale-to-fit math, dismiss guard via linkedom, tint/solidTint (21 tests incl. existing diagram-layout suite).

Verifier

One scoped fix: the bundled Tailwind CSS always contains SlideDeck's scroll-snap utilities, so detectProfile classified every fixed-stage artifact as slides and then failed deck-scroll-snap-axis against a deck that never scrolls. data-ve-presentation artifacts now verify as pages. ve-verify on the demo artifact: profile=page, errors=0 (1 warn: sub-44px hit targets, inherent to a scaled presenter stage). ve:eval (all 130+ seeded-violation fixtures) stays green with the detection change.

Demo

examples/visual-explainer-mdx/presentation-deck.tsx — 4 slides exercising engine + primitives, wired into ve:check. The slide-2 drill sheet doubles as the interaction fixture (one of every guarded element class).

Paper-ink preset	Terminal preset (same source)
	swap preset="terminal" — asserted by the preset-reskin eval

Test plan

• npm test — 21/21
• npm run ve:check — roster sync (incl. re-exports), all 15 example exports + SSR content probes, integrity fixtures
• npm run ve:eval — all seeded violations + clean fixtures pass with the profile-detection change
• npm run ve:eval-presentation — 17/17; each eval demonstrated falsifiable
• npm run check:manifests
• ve-verify on the exported demo: errors=0
• Playwright screenshots at 1440×900 and 1600×1000 (paper-ink + terminal, drill sheet open) confirm rendering

Docs

docs/presentation-deck.md (PresentationDeck vs SlideDeck), README, CHANGELOG (Unreleased), CONTRIBUTING (engine changes must run both suites), SKILL.md component roster.

🤖 Generated with Claude Code

2026-07-15: token eval generalized — instead of scanning for known-bad values, it now asserts the module ships zero color/font literals outside a documented allowlist (strictly stronger). Branch history rewritten before merge to keep the diff self-contained; content otherwise identical.

Coordination with PR #3 (design-system registry): the branches conflict in 6 files (package.json scripts, scripts/ve-mdx/check.mjs roster guard, visual-explainer-mdx/components.tsx VisualPreset/exports, CHANGELOG, README, SKILL.md) — all additive; whichever lands second rebases. One resolution rule: the components.tsx VisualPreset conflict must resolve in favor of PR #3's registry-open type (… | (string & {})) or registry presets won't typecheck (this PR's PresentationDeck already takes preset: string, so it is compatible either way).