fix(frontend): issues from the 10-25 Chrome sweep

- Incident detail "← Incidents" used router.back(), so arriving from Live
  or a shared link it went to the map / out of the app. Now a Link.
- Resolved incidents showed "0m elapsed" (manual resolve sets no
  resolved_at, updated_at can predate the last call): end is now the
  latest of resolved_at, updated_at and the newest call.
- Admin: the max-width toggle wrapped the tab bar, so it reflowed on every
  tab switch and left the cursor over e.g. "Close calls". Body only now.
- STT Eval sat on "Loading…" forever when a scanned page had zero matches
  but a next_cursor — the refill effect didn't depend on cursor.
- Trip event blocks used dark-only bg-indigo-950/60: unreadable in light
  mode. Theme tokens now.
- Reassign modal said "connected for the first time" on configured nodes.
- Dark-mode placeholders dimmed + italic; they read as filled-in values.

Frontend unverified locally (no Node, #207); CI build typechecks.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-frontend/components/NodeConfigModal.tsx

@@ -54,8 +54,12 @@ export function NodeConfigModal({ node, systems, onClose }: Props) {
       <div className="bg-surface border border-line-strong rounded-xl p-6 w-full max-w-md font-mono max-h-[90vh] overflow-y-auto">
         <h2 className="text-white font-semibold mb-1">Configure Node</h2>
         <p className="text-ink-2 text-sm mb-5">
-          <span className="text-indigo-400">{node.node_id}</span> connected for the first time.
-          Assign it a radio system to begin monitoring.
+          {node.configured ? (
+            <><span className="text-indigo-400">{node.node_id}</span>: choose the radio system it should monitor.</>
+          ) : (
+            <><span className="text-indigo-400">{node.node_id}</span> connected for the first time.
+            Assign it a radio system to begin monitoring.</>
+          )}
         </p>
 
         <form onSubmit={handleSubmit} className="space-y-4">