…ision (CODEAI-696) (#416)

* fix(wix-headless): move spacing to Tailwind's numeric scale, killing the max-w-<size> collision (CODEAI-696)

Root cause: compose.mjs emitted a named --spacing-* scale using t-shirt sizes
(md, 3xl, …). In Tailwind v4 the width family (max-w-/w-/min-w-) is generated
from the --spacing-* namespace, so `max-w-3xl` resolved to --spacing-3xl
(~96px) instead of --container-3xl — collapsing any LLM/author-written reading
column to one word per line. Hand-written templates dodged it; generated layout
(#411/#412) tripped it.

Fix — adopt Tailwind v4's built-in numeric spacing (the skill's values already
match it 1:1, e.g. md=1rem=`4`, 4xl=6rem=`24`), removing the named scale so
nothing collides with width keys:
- compose.mjs: stop emitting named --spacing-*; drop it from REQUIRED, the
  DESIGN.md read, and the container≠spacing check. Tailwind's --spacing base
  (numeric gap-4/py-24/…) is used directly. Containers kept — now max-w-md/3xl/6xl
  resolve to --container-* correctly.
- emit-design-tokens.mjs: stop projecting named --spacing-* into design-tokens.css
  / site.d.ts.
- Migrated 112 spacing utility classes (gap-md→gap-4, py-4xl→py-24, …) and 122
  var(--spacing-*) refs (→ literal rem) across 27 template + instruction-doc files.
- Spec docs (DESIGN_MD, DESIGN_SYSTEM, STYLING): dropped the spacing token group
  (Designer no longer authors spacing) and corrected STYLING's (wrong) claim that
  max-w-3xl maps to --container-3xl.

Verified: compose emits 0 --spacing-* and the 4 --container-* tokens; 0 leftover
t-shirt spacing classes/var refs across templates+docs; both scripts parse.
Live compiled-CSS/Playwright proof pending a network-capable build env.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(wix-headless): drop stale var(--spacing-*) fallback guidance in gift-cards COMPONENTS (CODEAI-696)

The gift-cards component doc still told authors to fall back to var(--spacing-*),
which no longer exists after the numeric-spacing migration. Point at Tailwind's
numeric spacing instead.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(wix-headless): address #416 review — purge stale --spacing-* references (CODEAI-696)

Review (adimara) flagged comments/docs that still referenced the removed named
--spacing-* scale, plus a real breakage the main-merge re-introduced.

Doc/comment fixes (stale references):
- templates/global.css @theme comment: drop --spacing-* from the substituted
  list; reframe as "spacing is Tailwind numeric; never add --spacing-* (it powers
  the width utilities)".
- gift-cards/components-gift-cards.css header: drop --spacing-{…} from reused tokens.
- bookings/services/[slug].astro: the max-w warning's spacing-fallback rationale is
  obsolete post-fix — reframed (max-w-* now resolves to --container-*).
- stores/ecom/COMPONENTS_CSS.md, shared/IMPLEMENTER.md: drop `spacing` from the
  DESIGN.md vocabulary list; swap the --spacing-md token example for --radius-md.
- designer/INSTRUCTIONS.md: "spacing scale from @theme" → Tailwind numeric.

Real functional fix:
- bookings/components-bookings.css: the merged-in bookings rewrite (610d0ea) shipped
  6 var(--spacing-sm/md/xl/xs) refs that resolve to nothing after the fix — migrated
  to literal rem (sm=.75 md=1 lg=1.5 xl=2 xs=.5).

Forward guard (review point on namespace fragility):
- STYLING.md: note that --spacing-* must never be reintroduced (it shadows max-w-*);
  custom spacing *values* should use a different namespace (e.g. --rhythm-*).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>