feat: add Study Brain foundation with schema, agent, and study-plan UI

app/(app)/past_papers/[code]/[exam]/page.tsx

@@ -21,6 +21,7 @@ import {
     getCourseSyllabusPath,
 } from "@/lib/seo";
 import CourseHeader from "@/app/components/past_papers/course-header";
+import StudyPlanCta from "@/app/components/study-plan/plan-cta";
 import CoursePaperGrid from "@/app/components/past_papers/course-paper-grid";
 import {
     DESKTOP_SELECT_ALL_HOST_ID,
@@ -191,7 +192,9 @@ async function CourseExamContent({
                         ]}
                     />
 
-                <section className="rounded-md border border-black/10 bg-white p-4 dark:border-[#D5D5D5]/10 dark:bg-[#0C1222]">
+                    <StudyPlanCta courseCode={course.code} examType={examType} />
+
+                    <section className="rounded-md border border-black/10 bg-white p-4 dark:border-[#D5D5D5]/10 dark:bg-[#0C1222]">
                     <p className="sr-only">
                         Open the dedicated {label} collection for {course.code} when you want a
                         focused set of papers for one exam pattern instead of the full course list.

app/(app)/past_papers/[code]/page.tsx

@@ -34,6 +34,7 @@ import {
 } from "@/app/components/past_papers/course-paper-grid-controls";
 import CoursePagination from "@/app/components/past_papers/course-pagination";
 import CourseVisitTracker from "@/app/components/past_papers/course-visit-tracker";
+import StudyPlanCta from "@/app/components/study-plan/plan-cta";
 import {
     campusValues,
     course as courseTable,
@@ -602,6 +603,7 @@ async function CoursePastPapersPageContent({
                     noteCount={course.noteCount}
                     syllabusId={null}
                 >
+                    <StudyPlanCta courseCode={course.code} variant="compact" />
                     <Suspense fallback={null}>
                         <CourseHeaderSyllabusAction
                             code={course.code}
@@ -610,6 +612,8 @@ async function CoursePastPapersPageContent({
                     </Suspense>
                 </CourseHeader>
 
+                <StudyPlanCta courseCode={course.code} />
+
                 <Suspense fallback={<CoursePastPapersSectionsShell />}>
                     <CoursePastPapersContent
                         course={course}

app/(app)/study-plan/page.tsx

@@ -0,0 +1,92 @@
+import type { Metadata } from "next";
+import DirectionalTransition from "@/app/components/common/directional-transition";
+import StudyPlanExperience from "@/app/components/study-plan/study-plan-experience";
+import StructuredData from "@/app/components/seo/structured-data";
+import {
+  getCoursePickerRecords,
+  getUpcomingExamsCourseGrid,
+  type CourseSearchRecord,
+} from "@/lib/data/course-catalog";
+import { buildBreadcrumbList } from "@/lib/structured-data";
+
+type CoursePick = {
+  id: string;
+  code: string;
+  title: string;
+  paperCount: number;
+};
+
+type SearchParams = {
+  course?: string;
+  exam?: string;
+  slot?: string;
+};
+
+export const metadata: Metadata = {
+  title: "Study plan | ExamCooker",
+  description:
+    "Build a syllabus-grounded study queue from ExamCooker past papers, slot reports, resources, and web research.",
+  alternates: { canonical: "/study-plan" },
+};
+
+export default async function StudyPlanPage({
+  searchParams,
+}: {
+  searchParams?: Promise<SearchParams>;
+}) {
+  const [params, courses, upcoming] = await Promise.all([
+    searchParams ?? Promise.resolve({} as SearchParams),
+    getCoursePickerRecords(),
+    getUpcomingExamsCourseGrid(),
+  ]);
+
+  // Resolve the curated upcoming-exam courses to full search records (keeping
+  // the curated order) so they can seed the planner as one-tap entry points.
+  const byCode = new Map(courses.map((course) => [course.code, course]));
+  const suggested: CoursePick[] = upcoming
+    .map((item) => byCode.get(item.code))
+    .filter((course): course is CourseSearchRecord => Boolean(course));
+
+  // A second band of real entry points: the courses with the most material that
+  // aren't already shown as upcoming exams. Always full, always useful.
+  const upcomingCodes = new Set(upcoming.map((item) => item.code));
+  const popularPicks: CoursePick[] = courses
+    .filter((course) => !upcomingCodes.has(course.code) && course.paperCount > 0)
+    .sort((a, b) => b.paperCount - a.paperCount)
+    .slice(0, 12)
+    .map((course) => ({
+      id: course.id,
+      code: course.code,
+      title: course.title,
+      paperCount: course.paperCount,
+    }));
+
+  return (
+    <DirectionalTransition>
+      <main className="relative min-h-dvh overflow-hidden bg-[#C2E6EC] text-black dark:bg-[hsl(224,48%,9%)] dark:text-[#D5D5D5]">
+        <StructuredData
+          data={[
+            buildBreadcrumbList([
+              { name: "Home", path: "/" },
+              { name: "Study plan", path: "/study-plan" },
+            ]),
+          ]}
+        />
+        <div
+          aria-hidden
+          className="pointer-events-none absolute inset-x-0 top-0 z-0 h-[520px] bg-[radial-gradient(72%_100%_at_22%_-10%,rgba(39,186,236,0.10),transparent_62%)] dark:bg-[radial-gradient(72%_100%_at_22%_-10%,rgba(39,186,236,0.14),transparent_60%)]"
+        />
+        <div className="relative z-10 mx-auto flex w-full max-w-7xl flex-col gap-6 px-3 py-6 sm:px-6 sm:py-8 lg:px-10 lg:py-12">
+          <StudyPlanExperience
+            courses={courses}
+            suggested={suggested}
+            popular={popularPicks}
+            initialCourse={params.course ?? ""}
+            initialExam={params.exam ?? ""}
+            initialSlot={params.slot ?? ""}
+          />
+        </div>
+      </main>
+    </DirectionalTransition>
+  );
+}

app/(app)/syllabus/course/[code]/page.tsx

@@ -9,6 +9,7 @@ import ViewTracker from "@/app/components/view-tracker";
 import { LazySyllabusInlineEditor } from "@/app/components/moderation/lazy-editors";
 import StructuredData from "@/app/components/seo/structured-data";
 import DirectionalTransition from "@/app/components/common/directional-transition";
+import StudyPlanCta from "@/app/components/study-plan/plan-cta";
 import { getCourseByCodeAny } from "@/lib/data/courses";
 import { getCourseDetailByCode } from "@/lib/data/course-catalog";
 import { getSubjectByCourseCode } from "@/lib/data/resources";
@@ -189,6 +190,8 @@ async function CourseSyllabusContent({
                         </div>
                     </header>
 
+                    <StudyPlanCta courseCode={context.code} />
+
                     <div className="overflow-hidden border border-black/15 bg-white shadow-[0_4px_28px_-14px_rgba(0,0,0,0.25)] dark:border-[#D5D5D5]/15 dark:bg-[#0C1222] dark:shadow-[0_4px_28px_-14px_rgba(0,0,0,0.6)]">
                         <div className="h-[70dvh] sm:h-[78dvh] lg:h-[84dvh] xl:h-[86dvh]">
                             <PDFViewerClient