feat: dashboard UI/UX overhaul from full review

Shared foundation:
- New Modal component on native <dialog>.showModal() (focus trap, inert
  background, Escape, focus restore, scroll lock); all eight dialogs and
  both globalThis.confirm calls migrated to it
- Design tokens for success/warning/danger surfaces; pill danger variant;
  .sr-only utility; toast layering above dialog backdrops; not-allowed
  cursor for validity-disabled buttons

Conversations/attention: auto-scroll with jump-to-latest, per-conversation
draft persistence, suggestion undo, 30s auto-refresh with refresh controls,
unread emphasis and counts, blur-consistent share dialog, empty-accounts
guidance, collapsed user lookup, relative timestamps, danger pills for
critical items

Media/library/outreach: click-blurred-to-reveal, lightbox with arrow
navigation and captions, dirty-form preservation across refetches, upload
validation with thumbnail preview, save feedback, result counts with
load-more and clear-filters, ticking countdowns from a single clock

Overview/performance/operations/settings: mutation errors inside the
confirm dialog, live sending-window countdown, offline-aware loading
states, per-panel loading/error with retry, 7/30/90-day range toggle,
console scroll yielding with shown/retained counts, risky-save matching
by subreddit name instead of index, useBlocker unsaved-changes guard,
single-pass validation with focus-to-first-error, access panel JSON
validation and input reset

Tests: 806 -> 844 passing; both typechecks clean.

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

apps/dashboard/src/features/settings/risk-dialog.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useRef } from 'react';
+import { Modal } from '../../components/modal.js';
 
 interface RiskDialogProps {
   reasons: string[];
@@ -8,27 +8,19 @@ interface RiskDialogProps {
 }
 
 export function RiskDialog({ reasons, isPending, onCancel, onConfirm }: RiskDialogProps) {
-  const cancelButtonRef = useRef<HTMLButtonElement>(null);
-
-  useEffect(() => {
-    cancelButtonRef.current?.focus();
-  }, []);
-
   return (
-    <div aria-labelledby="risk-settings-title" aria-modal="true" className="dialog-backdrop" role="dialog">
-      <div className="dialog-card">
-        <span className="eyebrow">Confirm operational risk</span>
-        <h2 id="risk-settings-title">Confirm risky settings</h2>
-        <ul className="risk-list">
-          {reasons.map((reason) => <li key={reason}>{reason}</li>)}
-        </ul>
-        <div className="dialog-actions">
-          <button className="button secondary" disabled={isPending} onClick={onCancel} ref={cancelButtonRef} type="button">Cancel</button>
-          <button className="button danger" disabled={isPending} onClick={onConfirm} type="button">
-            {isPending ? 'Applying…' : 'Apply risky settings'}
-          </button>
-        </div>
+    <Modal className="dialog-card" isDismissLocked={isPending} labelledBy="risk-settings-title" onClose={onCancel}>
+      <span className="eyebrow">Confirm operational risk</span>
+      <h2 id="risk-settings-title">Confirm risky settings</h2>
+      <ul className="risk-list">
+        {reasons.map((reason) => <li key={reason}>{reason}</li>)}
+      </ul>
+      <div className="dialog-actions">
+        <button autoFocus className="button secondary" disabled={isPending} onClick={onCancel} type="button">Cancel</button>
+        <button className="button danger" disabled={isPending} onClick={onConfirm} type="button">
+          {isPending ? 'Applying…' : 'Apply risky settings'}
+        </button>
       </div>
-    </div>
+    </Modal>
   );
 }