feat: implement database entities, repository, controllers, and data seeder for Notes & PYQs module

backend/src/main/java/com/rit/portal/controller/NotePyqController.java

@@ -0,0 +1,52 @@
+package com.rit.portal.controller;
+
+import com.rit.portal.entity.NotePyq;
+import com.rit.portal.repository.NotePyqRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+import java.util.List;
+
+@RestController
+@RequestMapping("/api/notes")
+@CrossOrigin(origins = "*") // CrossOrigin configured globally, but added here for safety
+public class NotePyqController {
+
+    @Autowired
+    private NotePyqRepository noteRepository;
+
+    // Get all notes
+    @GetMapping
+    public List<NotePyq> getAllNotes() {
+        return noteRepository.findAll();
+    }
+
+    // Get notes by semester
+    @GetMapping("/semester/{semester}")
+    public List<NotePyq> getNotesBySemester(@PathVariable Integer semester) {
+        return noteRepository.findBySemester(semester);
+    }
+
+    // Get notes by department
+    @GetMapping("/department")
+    public List<NotePyq> getNotesByDepartment(@RequestParam String dept) {
+        return noteRepository.findByDepartment(dept);
+    }
+
+    // Add a new note metadata
+    @PostMapping
+    public NotePyq createNote(@RequestBody NotePyq note) {
+        return noteRepository.save(note);
+    }
+
+    // Increment downloads count
+    @PostMapping("/{id}/download")
+    public ResponseEntity<Void> incrementDownloads(@PathVariable Long id) {
+        return noteRepository.findById(id).map(note -> {
+            note.setDownloadsCount(note.getDownloadsCount() + 1);
+            note.setFileType(note.getFileType()); // Keep dirty check
+            noteRepository.save(note);
+            return ResponseEntity.ok().<Void>build();
+        }).orElse(ResponseEntity.notFound().build());
+    }
+}