UI/UX audit fixes: clickable pipelines, broken links, isActive locking

- Make pipeline cards clickable on list page (navigate to detail view)
- Fix broken nav link: applicant /messages → /mentor
- Fix broken nav link: mentor /messages → /projects
- Add isActive field locking to all 7 wizard sections (intake, main-track,
  filtering, assignment, awards, live-finals, notifications)
- Add minLoad ≤ maxLoad cross-field validation in assignment section
- Add duplicate stage slug detection in main track section
- Add active pipeline warning banners in intake and main track sections

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

src/components/admin/pipeline/sections/intake-section.tsx

@@ -18,9 +18,10 @@ import type { IntakeConfig, FileRequirementConfig } from '@/types/pipeline-wizar
 type IntakeSectionProps = {
   config: IntakeConfig
   onChange: (config: IntakeConfig) => void
+  isActive?: boolean
 }
 
-export function IntakeSection({ config, onChange }: IntakeSectionProps) {
+export function IntakeSection({ config, onChange, isActive }: IntakeSectionProps) {
   const updateConfig = (updates: Partial<IntakeConfig>) => {
     onChange({ ...config, ...updates })
   }
@@ -54,6 +55,12 @@ export function IntakeSection({ config, onChange }: IntakeSectionProps) {
 
   return (
     <div className="space-y-6">
+      {isActive && (
+        <p className="text-sm text-amber-600 bg-amber-50 rounded-md px-3 py-2">
+          Some settings are locked because this pipeline is active.
+        </p>
+      )}
+
       {/* Submission Window */}
       <div className="space-y-4">
         <div className="flex items-center justify-between">
@@ -68,6 +75,7 @@ export function IntakeSection({ config, onChange }: IntakeSectionProps) {
             onCheckedChange={(checked) =>
               updateConfig({ submissionWindowEnabled: checked })
             }
+            disabled={isActive}
           />
         </div>
       </div>
@@ -83,6 +91,7 @@ export function IntakeSection({ config, onChange }: IntakeSectionProps) {
                 lateSubmissionPolicy: value as IntakeConfig['lateSubmissionPolicy'],
               })
             }
+            disabled={isActive}
           >
             <SelectTrigger>
               <SelectValue />
@@ -115,7 +124,7 @@ export function IntakeSection({ config, onChange }: IntakeSectionProps) {
       <div className="space-y-3">
         <div className="flex items-center justify-between">
           <Label>File Requirements</Label>
-          <Button type="button" variant="outline" size="sm" onClick={addFileReq}>
+          <Button type="button" variant="outline" size="sm" onClick={addFileReq} disabled={isActive}>
             <Plus className="h-3.5 w-3.5 mr-1" />
             Add Requirement
           </Button>
@@ -183,6 +192,7 @@ export function IntakeSection({ config, onChange }: IntakeSectionProps) {
                   size="icon"
                   className="shrink-0 text-muted-foreground hover:text-destructive"
                   onClick={() => removeFileReq(index)}
+                  disabled={isActive}
                 >
                   <Trash2 className="h-4 w-4" />
                 </Button>