DS1 (design): speed + trust bugs

Fixes the three DESIGN-SPEC Part 4 + #17 audit findings.

1. React #418 hydration mismatch (landing → dashboard entry). The
   `maybeSignedIn` value was computed in a useState INITIALIZER that reads
   localStorage during render: server (no window) → false → emits the
   marketing tree; a signed-in visitor's first CLIENT render → true → emits
   the loading placeholder. Whole-subtree server/client mismatch → React
   discarded and re-rendered the page. Deferred behind a mounted flag so the
   first client render matches the server; the stored-session check flips
   post-mount. SSR HTML is no longer discarded.

2. Loading walls → skeletons. New tokenized Skeleton primitive
   (.vyndr-skeleton, reduced-motion-safe via the global rule). Swapped into
   every text-wall loader: dashboard slate load ("Loading the slate…"), /desk
   ("Assembling the pack…"), /ledger ("Loading…"), scan ("Loading the model…"),
   and the landing redirect placeholder. No bare text loader remains.

3. scan→ledger persistence. Root cause: the scan page read its bearer token
   from localStorage['sb-token'] — a key written ONLY by the OAuth callback —
   so email/password users posted /api/scan anonymously and the ledger write
   (gated on an authed user) was silently skipped. Now uses the authoritative
   session.access_token (matching the ledger read path). Extracted the row
   builder to web/src/lib/ledgerRow.js (shared, testable).

Tests: +17 (scanLedgerPersistence write→mine round-trip + scope + idempotency;
ds1SpeedTrust hydration/skeleton/persistence source invariants). Full suite
233 suites / 2793 green; web build exit 0.

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

web/src/app/dashboard/page.tsx

@@ -10,7 +10,7 @@ import { GradePill } from '@/components/GradeCard';
 // below as intelligence layers on top of the raw odds.
 import Slate from '@/components/Slate';
 // Session 55 — the self-learning loop's track record, live in the header.
-import { AccuracyBadge } from '@/components/vyndr';
+import { AccuracyBadge, Skeleton, SkeletonList } from '@/components/vyndr';
 // Session 57 (Phase 0) — honest per-sport empty-slate copy.
 import { emptyStateCopy } from '@/lib/emptyState';
 // Session 59 (work-order 2.3) — the real pipeline schedule for waiting states.
@@ -181,9 +181,15 @@ export default function DashboardPage() {
   }, [user]);
 
   if (authLoading || !user) {
+    // DS1 (§4) — layout-matched skeleton, never a text wall. Mirrors the real
+    // dashboard: header strip + a stack of slate cards.
     return (
-      <section style={{ minHeight: '80vh', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
-        <p className="mono" style={{ color: 'var(--text-tertiary)' }}>Loading the slate…</p>
+      <section style={{ maxWidth: 1100, margin: '0 auto', padding: '24px 16px 120px' }} aria-busy="true">
+        <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: 24, gap: 16 }}>
+          <Skeleton height={30} width={220} radius={10} />
+          <Skeleton height={30} width={120} radius={999} />
+        </div>
+        <SkeletonList count={5} height={92} />
       </section>
     );
   }