Remove Mistake Analyzer and rename Mistake Heatmap to Mastery Map

src/app/dashboard/ai-coach/heatmap/page.tsx

@@ -1,4 +1,4 @@
-"use client"
+"use client"
 
 import { MistakeHeatmap } from "@/components/AI/MistakeHeatmap"
 import { Flame, AlertTriangle, TrendingDown, BookOpen, ArrowRight, BarChart2, Target, CheckCircle2 } from "lucide-react"
@@ -44,7 +44,7 @@ export default function HeatmapPage() {
               <span className="p-2.5 rounded-xl bg-cyan-50 dark:bg-[var(--cyan-ai-10)] border border-cyan-300/60 dark:border-[var(--cyan-ai-20)]">
                 <Flame className="text-cyan-700 dark:text-[var(--cyan-ai)]" size={28} />
               </span>
-              Mistake Heatmap Vault
+              Mastery Map Vault
             </h1>
             <p className="text-muted-foreground text-base font-medium max-w-2xl pl-1">
               Visual density map of your errors across subjects and topics — pinpoint your weakest areas instantly.
@@ -148,7 +148,6 @@ export default function HeatmapPage() {
               <h3 className="text-sm font-black uppercase tracking-wider text-[var(--cyan-ai)]">What To Do Next</h3>
               <div className="space-y-2">
                 {[
-                  { label: "Start Mistake Review Session", href: "/dashboard/ai-coach/mistakes" },
                   { label: "Take a Physics DPP", href: "/dashboard/ai-coach/cbt-dpp" },
                   { label: "Check Exam Readiness Score", href: "/dashboard/ai-coach/readiness" },
                 ].map((link) => (