0595 — spacing token scale: exact values, pixel-value names, one tier

Context

website/CONVENTIONS.md has declared spacing a closed token scale since the CSS rules were written, but every component stylesheet still carried raw px. The values in use are hand-tuned pixel-era spacing: every integer 1–14, then 16, 18, 20, 22, 24, 26, 32, 34 — 22 distinct steps across 36 component stylesheets, three layout scoped blocks, and the global base/utilities layers.

Decision

• The scale IS the set in use: --space-1 … --space-34, each step named by its pixel value, defined once in the tokens layer beside the z-index scale. No snapping to a sparser ladder — the sweep is behavior-preserving; merging 9 into 8 or 13 into 12 is a visible design change that would need eyeballing every spot, and nothing asked for a redesign. Consolidation stays available later as its own pass, now enumerable in one place.
• Pixel-value names, not size names (--space-sm) — with 22 steps a size ladder is meaningless, and the naming rule is the thing it literally is. The name spells the value, so a step’s meaning never drifts from its label.
• One tier, like --z-raised: spacing is structural, stated once, style-independent — a board style never redefines it.
• Scope is the spacing properties only: margin, padding, gap and their longhands. Positioning coordinates (the pixel-art components’ top/left), border widths, and sizes stay raw px — they are drawing and sizing, not spacing.
• Enforcement: /^margin/, /^padding/, /gap$/ join the declaration-strict-value property list; 0 and auto join ignoreValues. The one negative use writes calc(-1 * var(--space-34)).

Consequences

• Zero visual change; full site verify floor green.
• A new spacing value cannot enter silently — stylelint fails the build until a step is added to the scale deliberately. Sabotage-checked: the rule catches raw px in shorthands mixed with tokens (margin: var(--space-8) 0 3px) and in logical properties (padding-inline).
• The layout .astro scoped blocks are swept but outside stylelint’s src/**/*.css glob — review carries them.
• The scale is wide (22 steps). That is the honest state of the design, not a target; shrinking it is a future design decision, not cleanup.