feat(v3): restructure project + add complete frontend

- Restructure: move backend from new_project/ to backend/
- Add full React/TypeScript frontend (37 pages, 17 services, 16 type defs, 11 query hooks)
- Add docs/ with SRS specs, user stories, and workflow documentation
- Update .gitignore for new directory layout

Workflows implemented:
  WF1 User Signup, WF2 Placement Test, WF3 Exam Configuration,
  WF4 General English Exam, WF5 Course Generation,
  WF6 Entity Student Onboarding, AI Course Generation,
  Adaptive Learning Engine UI, White-Label Branding, Score Release

Made-with: Cursor

src/components/ai/AiGradeExplainer.tsx

@@ -0,0 +1,78 @@
+import { useState } from "react";
+import { useMutation } from "@tanstack/react-query";
+import { Button } from "@/components/ui/button";
+import { Dialog, DialogContent, DialogHeader, DialogTitle } from "@/components/ui/dialog";
+import { Sparkles, Loader2 } from "lucide-react";
+import { coachingService } from "@/services/coaching.service";
+import { useToast } from "@/hooks/use-toast";
+
+export default function AiGradeExplainer({
+  studentName,
+  scores,
+}: {
+  studentName: string;
+  scores?: Record<string, number>;
+}) {
+  const [open, setOpen] = useState(false);
+  const { toast } = useToast();
+
+  const explainMutation = useMutation({
+    mutationFn: () =>
+      coachingService.explain({
+        context: `IELTS / course grades for student: ${studentName}. Summarize what the scores mean and what to focus on next.`,
+        scores,
+      }),
+    onError: (err: Error) => {
+      toast({
+        variant: "destructive",
+        title: "Could not explain grades",
+        description: err.message || "Try again in a moment.",
+      });
+    },
+  });
+
+  const handleOpen = () => {
+    setOpen(true);
+    explainMutation.reset();
+    explainMutation.mutate();
+  };
+
+  return (
+    <>
+      <Button variant="ghost" size="icon" className="h-7 w-7" onClick={handleOpen} title="AI Explain Grade">
+        <Sparkles className="h-3.5 w-3.5 text-primary" />
+      </Button>
+      <Dialog
+        open={open}
+        onOpenChange={(v) => {
+          setOpen(v);
+          if (!v) explainMutation.reset();
+        }}
+      >
+        <DialogContent className="max-w-md">
+          <DialogHeader>
+            <DialogTitle className="flex items-center gap-2">
+              <Sparkles className="h-4 w-4 text-primary" />
+              AI Grade Explanation — {studentName}
+            </DialogTitle>
+          </DialogHeader>
+          {explainMutation.isPending ? (
+            <div className="flex items-center gap-2 text-sm text-muted-foreground py-6 justify-center">
+              <Loader2 className="h-5 w-5 animate-spin text-primary" /> Analyzing grades...
+            </div>
+          ) : explainMutation.isError ? (
+            <p className="text-sm text-destructive text-center py-4">
+              Something went wrong. Close and try again.
+            </p>
+          ) : (
+            <div className="rounded-lg bg-muted/30 p-4">
+              <p className="text-sm leading-relaxed">
+                {explainMutation.data?.explanation}
+              </p>
+            </div>
+          )}
+        </DialogContent>
+      </Dialog>
+    </>
+  );
+}