UI/UX redesign: unified refined-glass design system

- Add shared UI primitives: Button, Field/Input/Select, PageHeader,
  Section, Callout, Tabs, Disclosure
- Replace gradient buttons with single blue-accent btn-primary
- Reserve gradient text for the brand wordmark only
- Rework Scanner page onto the glass system; collapse explainer and
  glossary into a disclosure, move filters into a glass toolbar
- Restructure Ticker Detail into tabs (Analysis / Indicators / S/R)
  with chart and recommendation always visible
- Align Watchlist, Rankings, Admin, Login/Register to shared primitives
- Unify stray indigo/violet/gray accents into the blue family

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/components/admin/JobControls.tsx

@@ -188,7 +188,7 @@ export function JobControls() {
                 type="button"
                 onClick={() => triggerJob.mutate(job.name)}
                 disabled={triggerJob.isPending || !job.enabled || anyJobRunning}
-                className="btn-gradient px-3 py-1.5 text-xs disabled:opacity-50 disabled:cursor-not-allowed"
+                className="btn-primary px-3 py-1.5 text-xs disabled:opacity-50 disabled:cursor-not-allowed"
               >
                 <span>
                   {job.running