feat(sync): /api/sync/health endpoint + dashboard health pill + MALFORMED UI

Backend:
- GET /api/sync/health returns {last_sync_at, last_sync_status,
  last_halt_reason, recent_phase_failures, escalation_phase, is_healthy}.
  healthy when last run was completed (or none yet), no phase has
  tripped the 3-in-a-row escalation, and recent failures <= 1.
- Dashboard + run-level endpoints include `malformed` count so the
  Defecte pill can render.

Frontend:
- Health pill in .sync-card-controls with three states — healthy
  (success green, check icon), warning (amber, triangle), escalated
  (error red, x-octagon + glow). Tooltip exposes the halt reason and
  the top phases with recent failures.
- Status-dot + badge add MALFORMED treatment via --compare orange,
  distinct from ERROR red. DESIGN.md notes the diagnostic rationale
  (ERROR = runtime, MALFORMED = payload source issue).
- Defecte filter pill on dashboard + logs pages. Mobile segmented
  control includes Defecte count. Counts wired to the malformed key.
- startSync() shows a native confirm modal when state is
  halted_escalation — operator override still possible, not silenced.
- ORDER_STATUS.MALFORMED mirror added to shared.js.
- Cache-bust: style.css v46, shared.js v47, dashboard.js v52,
  logs.js v16.

5 endpoint tests cover empty state, completed, failed, escalated,
single-failure warning. Full CI: 257 unit + 33 e2e green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/app/static/css/style.css

@@ -495,6 +495,7 @@ input[type="checkbox"] {
 .dot-yellow { background: var(--warning); box-shadow: 0 0 6px 2px rgba(202,138,4,0.3); }
 .dot-red    { background: var(--error); box-shadow: 0 0 8px 2px rgba(220,38,38,0.35); }
 .dot-gray   { background: var(--cancelled); }
+.dot-orange { background: var(--compare); box-shadow: 0 0 8px 2px rgba(234,88,12,0.35); }
 .dot-blue   { background: var(--info); }
 
 /* ── Flat row (mobile + desktop) ────────────────── */
@@ -805,6 +806,45 @@ tr.mapping-deleted td {
 .sync-status-dot.running   { background: var(--info); animation: pulse-dot 2s ease-in-out infinite; }
 .sync-status-dot.completed { background: var(--success); }
 .sync-status-dot.failed    { background: var(--error); }
+.sync-status-dot.malformed { background: var(--compare); box-shadow: 0 0 8px 2px rgba(234,88,12,0.35); }
+
+/* ── Sync health pill (dashboard only) ────────────── */
+.health-pill {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.375rem;
+    padding: 0.375rem 0.625rem;
+    min-height: 32px;
+    border-radius: 999px;
+    font-size: 0.8125rem;
+    line-height: 1;
+    font-weight: 500;
+    border: 1px solid transparent;
+    cursor: default;
+    user-select: none;
+    transition: background 120ms ease;
+}
+.health-pill i { font-size: 0.9375rem; line-height: 1; }
+.health-pill.healthy {
+    background: var(--success-light);
+    color: var(--success-text);
+    border-color: var(--success);
+}
+.health-pill.warning {
+    background: var(--warning-light);
+    color: var(--warning-text);
+    border-color: var(--warning);
+}
+.health-pill.escalated {
+    background: var(--error-light);
+    color: var(--error-text);
+    border-color: var(--error);
+    box-shadow: 0 0 8px 2px rgba(220,38,38,0.35);
+}
+/* Ensure adequate touch target on mobile */
+@media (max-width: 600px) {
+    .health-pill { min-height: 44px; padding: 0.5rem 0.75rem; }
+}
 
 /* ── Custom period range inputs ──────────────────── */
 .period-custom-range {