实现快传，完善快传和网盘的功能，实现文件的互传等一系列功能

backend/sql/mysql-init.sql

@@ -7,8 +7,6 @@ CREATE TABLE IF NOT EXISTS portal_user (
     email VARCHAR(128) NOT NULL,
     password_hash VARCHAR(255) NOT NULL,
     created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    last_school_student_id VARCHAR(64),
-    last_school_semester VARCHAR(64),
     CONSTRAINT uk_portal_user_username UNIQUE (username),
     CONSTRAINT uk_portal_user_email UNIQUE (email)
 );
@@ -27,35 +25,5 @@ CREATE TABLE IF NOT EXISTS portal_file (
     CONSTRAINT uk_portal_file_user_path_name UNIQUE (user_id, path, filename)
 );
 
-CREATE TABLE IF NOT EXISTS portal_course (
-    id BIGINT PRIMARY KEY AUTO_INCREMENT,
-    user_id BIGINT NOT NULL,
-    course_name VARCHAR(255) NOT NULL,
-    semester VARCHAR(64),
-    student_id VARCHAR(64),
-    teacher VARCHAR(255),
-    classroom VARCHAR(255),
-    day_of_week INT,
-    start_time INT,
-    end_time INT,
-    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    CONSTRAINT fk_portal_course_user FOREIGN KEY (user_id) REFERENCES portal_user (id)
-);
-
-CREATE TABLE IF NOT EXISTS portal_grade (
-    id BIGINT PRIMARY KEY AUTO_INCREMENT,
-    user_id BIGINT NOT NULL,
-    course_name VARCHAR(255) NOT NULL,
-    grade DOUBLE NOT NULL,
-    semester VARCHAR(64) NOT NULL,
-    student_id VARCHAR(64),
-    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    CONSTRAINT fk_portal_grade_user FOREIGN KEY (user_id) REFERENCES portal_user (id)
-);
-
 CREATE INDEX idx_user_created_at ON portal_user (created_at);
 CREATE INDEX idx_file_created_at ON portal_file (created_at);
-CREATE INDEX idx_course_user_semester ON portal_course (user_id, semester, student_id);
-CREATE INDEX idx_course_user_created ON portal_course (user_id, created_at);
-CREATE INDEX idx_grade_user_semester ON portal_grade (user_id, semester, student_id);
-CREATE INDEX idx_grade_user_created ON portal_grade (user_id, created_at);