fix: navigation correctness - back buttons, exit dialog, dedup nav, redirects

- Standardize all procedural back/exit paths to /trees (not /my-trees)
- Add exit button with ConfirmDialog to procedural session top bar
- Consolidate duplicate account links in sidebar and topbar
- Auto-redirect non-owners to personal analytics
- Add toast feedback before silent permission redirects in tree editor
- Delete orphaned AdminCategoriesPage

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

frontend/src/pages/TeamAnalyticsPage.tsx

@@ -1,6 +1,6 @@
 import { useState, useEffect } from 'react'
-import { Link } from 'react-router-dom'
-import { BarChart3, Loader2, Users, Target, Clock, TrendingUp, ShieldX } from 'lucide-react'
+import { Link, Navigate } from 'react-router-dom'
+import { BarChart3, Loader2, Users, Target, Clock, TrendingUp } from 'lucide-react'
 import {
   AreaChart,
   Area,
@@ -44,25 +44,8 @@ export default function TeamAnalyticsPage() {
       .finally(() => setLoading(false))
   }, [period, isAccountOwner, isSuperAdmin])
 
-  // Permission guard
   if (!isAccountOwner && !isSuperAdmin) {
-    return (
-      <div className="flex flex-col items-center justify-center min-h-[60vh] gap-4 p-6">
-        <ShieldX size={48} className="text-muted-foreground" />
-        <h2 className="text-xl font-semibold text-foreground">Access Denied</h2>
-        <p className="text-muted-foreground text-center max-w-md">
-          Team Analytics is only available to account owners and administrators.
-          You can view your personal stats instead.
-        </p>
-        <Link
-          to="/analytics/me"
-          className="mt-2 inline-flex items-center gap-2 rounded-lg bg-white text-black px-4 py-2 text-sm font-medium hover:bg-white/90 transition-colors"
-        >
-          <TrendingUp size={16} />
-          View My Stats
-        </Link>
-      </div>
-    )
+    return <Navigate to="/analytics/me" replace />
   }
 
   if (loading) {