feat(ui): add auth pages, company rail, inbox redesign, and page improvements

Add Auth sign-in/sign-up page and InviteLanding page for invite acceptance.
Add CloudAccessGate that checks deployment mode and redirects to /auth when
session is required. Add CompanyRail with drag-and-drop company switching.
Add MarkdownBody prose renderer. Redesign Inbox with category filters and
inline join-request approval. Refactor AgentDetail to overview/configure/runs
views with claude-login support. Replace navigate() anti-patterns with <Link>
components in Dashboard and MetricCard. Add live-run indicators in sidebar
agents. Fix LiveUpdatesProvider cache key resolution for issue identifiers.
Add auth, health, and access API clients.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/pages/Goals.tsx

@@ -1,5 +1,4 @@
 import { useEffect } from "react";
-import { useNavigate } from "react-router-dom";
 import { useQuery } from "@tanstack/react-query";
 import { goalsApi } from "../api/goals";
 import { useCompany } from "../context/CompanyContext";
@@ -15,7 +14,6 @@ export function Goals() {
   const { selectedCompanyId } = useCompany();
   const { openNewGoal } = useDialog();
   const { setBreadcrumbs } = useBreadcrumbs();
-  const navigate = useNavigate();
 
   useEffect(() => {
     setBreadcrumbs([{ label: "Goals" }]);
@@ -47,13 +45,13 @@ export function Goals() {
 
       {goals && goals.length > 0 && (
         <>
-          <div className="flex items-center justify-end">
+          <div className="flex items-center justify-start">
             <Button size="sm" variant="outline" onClick={() => openNewGoal()}>
               <Plus className="h-3.5 w-3.5 mr-1.5" />
               New Goal
             </Button>
           </div>
-          <GoalTree goals={goals} onSelect={(goal) => navigate(`/goals/${goal.id}`)} />
+          <GoalTree goals={goals} goalLink={(goal) => `/goals/${goal.id}`} />
         </>
       )}
     </div>