feat: router.back() navigation, read-only evaluation view, auth audit logging

- Convert all Back buttons platform-wide (38 files) to use router.back()
  for natural browser-back behavior regardless of entry point
- Add read-only view for submitted evaluations in closed rounds with
  blue banner, disabled inputs, and contextual back navigation
- Add auth audit logs: MAGIC_LINK_SENT, PASSWORD_RESET_LINK_CLICKED,
  PASSWORD_RESET_LINK_EXPIRED, PASSWORD_RESET_LINK_INVALID
- Learning Hub links navigate in same window for all roles
- Update settings descriptions to reflect all-user scope

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

src/app/(mentor)/mentor/projects/[id]/page.tsx

@@ -1,8 +1,7 @@
 'use client'
 
 import { Suspense, use, useState, useEffect } from 'react'
-import Link from 'next/link'
-import type { Route } from 'next'
+import { useRouter } from 'next/navigation'
 import { trpc } from '@/lib/trpc/client'
 import {
   Card,
@@ -75,6 +74,7 @@ const statusColors: Record<string, 'default' | 'secondary' | 'destructive' | 'ou
 }
 
 function ProjectDetailContent({ projectId }: { projectId: string }) {
+  const router = useRouter()
   const { data: project, isLoading, error } = trpc.mentor.getProjectDetail.useQuery({
     projectId,
   })
@@ -106,11 +106,9 @@ function ProjectDetailContent({ projectId }: { projectId: string }) {
   if (error || !project) {
     return (
       <div className="space-y-6">
-        <Button variant="ghost" asChild className="-ml-4">
-          <Link href={'/mentor' as Route}>
-            <ArrowLeft className="mr-2 h-4 w-4" />
-            Back to Dashboard
-          </Link>
+        <Button variant="ghost" className="-ml-4" onClick={() => router.back()}>
+          <ArrowLeft className="mr-2 h-4 w-4" />
+          Back
         </Button>
 
         <Card>
@@ -122,8 +120,8 @@ function ProjectDetailContent({ projectId }: { projectId: string }) {
             <p className="text-sm text-muted-foreground mt-1">
               You may not have access to view this project.
             </p>
-            <Button asChild className="mt-4">
-              <Link href={'/mentor' as Route}>Back to Dashboard</Link>
+            <Button className="mt-4" onClick={() => router.back()}>
+              Back
             </Button>
           </CardContent>
         </Card>
@@ -140,11 +138,9 @@ function ProjectDetailContent({ projectId }: { projectId: string }) {
     <div className="space-y-6">
       {/* Header */}
       <div className="flex items-center gap-4">
-        <Button variant="ghost" asChild className="-ml-4">
-          <Link href={'/mentor' as Route}>
-            <ArrowLeft className="mr-2 h-4 w-4" />
-            Back to Dashboard
-          </Link>
+        <Button variant="ghost" className="-ml-4" onClick={() => router.back()}>
+          <ArrowLeft className="mr-2 h-4 w-4" />
+          Back
         </Button>
       </div>
 

src/app/(mentor)/mentor/resources/[id]/page.tsx

@@ -1,8 +1,7 @@
 'use client'
 
 import { useEffect } from 'react'
-import { useParams } from 'next/navigation'
-import Link from 'next/link'
+import { useParams, useRouter } from 'next/navigation'
 import dynamic from 'next/dynamic'
 import { trpc } from '@/lib/trpc/client'
 import { Button } from '@/components/ui/button'
@@ -27,6 +26,7 @@ const ResourceRenderer = dynamic(
 
 export default function MentorResourceDetailPage() {
   const params = useParams()
+  const router = useRouter()
   const resourceId = params.id as string
 
   const { data: resource, isLoading, error } = trpc.learningResource.get.useQuery({ id: resourceId })
@@ -73,11 +73,9 @@ export default function MentorResourceDetailPage() {
             This resource may have been removed or you don't have access.
           </AlertDescription>
         </Alert>
-        <Button asChild>
-          <Link href="/mentor/resources">
-            <ArrowLeft className="mr-2 h-4 w-4" />
-            Back to Resources
-          </Link>
+        <Button onClick={() => router.back()}>
+          <ArrowLeft className="mr-2 h-4 w-4" />
+          Back
         </Button>
       </div>
     )
@@ -87,11 +85,9 @@ export default function MentorResourceDetailPage() {
     <div className="space-y-6">
       {/* Header */}
       <div className="flex items-center justify-between">
-        <Button variant="ghost" asChild className="-ml-4">
-          <Link href="/mentor/resources">
-            <ArrowLeft className="mr-2 h-4 w-4" />
-            Back to Resources
-          </Link>
+        <Button variant="ghost" className="-ml-4" onClick={() => router.back()}>
+          <ArrowLeft className="mr-2 h-4 w-4" />
+          Back
         </Button>
         <div className="flex items-center gap-2">
           {resource.externalUrl && (

src/app/(mentor)/mentor/workspace/[projectId]/page.tsx

@@ -1,8 +1,6 @@
 'use client'
 
-import { useParams } from 'next/navigation'
-import Link from 'next/link'
-import type { Route } from 'next'
+import { useParams, useRouter } from 'next/navigation'
 import { trpc } from '@/lib/trpc/client'
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
 import { Button } from '@/components/ui/button'
@@ -16,6 +14,7 @@ import { toast } from 'sonner'
 
 export default function MentorWorkspaceDetailPage() {
   const params = useParams()
+  const router = useRouter()
   const projectId = params.projectId as string
 
   // Get mentor assignment for this project
@@ -39,11 +38,9 @@ export default function MentorWorkspaceDetailPage() {
   if (!project) {
     return (
       <div className="space-y-6">
-        <Button variant="ghost" size="sm" asChild>
-          <Link href={'/mentor/workspace' as Route}>
-            <ArrowLeft className="mr-2 h-4 w-4" />
-            Back
-          </Link>
+        <Button variant="ghost" size="sm" onClick={() => router.back()}>
+          <ArrowLeft className="mr-2 h-4 w-4" />
+          Back
         </Button>
         <Card>
           <CardContent className="flex flex-col items-center justify-center py-12">
@@ -58,11 +55,9 @@ export default function MentorWorkspaceDetailPage() {
   return (
     <div className="space-y-6">
       <div className="flex items-center gap-4">
-        <Button variant="ghost" size="sm" asChild>
-          <Link href={'/mentor/workspace' as Route}>
-            <ArrowLeft className="mr-2 h-4 w-4" />
-            Back
-          </Link>
+        <Button variant="ghost" size="sm" onClick={() => router.back()}>
+          <ArrowLeft className="mr-2 h-4 w-4" />
+          Back
         </Button>
         <div className="flex-1">
           <div className="flex items-center gap-3 flex-wrap">

src/app/(mentor)/mentor/workspace/page.tsx

@@ -2,6 +2,7 @@
 
 import Link from 'next/link'
 import type { Route } from 'next'
+import { useRouter } from 'next/navigation'
 import { trpc } from '@/lib/trpc/client'
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
 import { Badge } from '@/components/ui/badge'
@@ -20,6 +21,7 @@ const statusColors: Record<string, 'default' | 'secondary' | 'destructive' | 'ou
 }
 
 export default function MentorWorkspacePage() {
+  const router = useRouter()
   const { data: assignments, isLoading } = trpc.mentor.getMyProjects.useQuery()
 
   if (isLoading) {
@@ -46,11 +48,9 @@ export default function MentorWorkspacePage() {
             Collaborate with your assigned mentee projects
           </p>
         </div>
-        <Button variant="ghost" size="sm" asChild>
-          <Link href={'/mentor' as Route}>
-            <ArrowLeft className="mr-2 h-4 w-4" />
-            Back to Dashboard
-          </Link>
+        <Button variant="ghost" size="sm" onClick={() => router.back()}>
+          <ArrowLeft className="mr-2 h-4 w-4" />
+          Back
         </Button>
       </div>