refactor(prisma): 将数据库从 SQLite 迁移至 PostgreSQL

删除 SQLite 相关依赖、配置和生成文件，更新 Prisma schema 以使用 PostgreSQL 作为数据源。
移除本地 dev.db 文件、libsql 适配器和旧迁移文件，简化 Prisma 客户端初始化。

backend/prisma/migrations/20260306034508_init/migration.sql

@@ -1,86 +0,0 @@
--- CreateTable
-CREATE TABLE "User" (
-    "id" TEXT NOT NULL PRIMARY KEY,
-    "name" TEXT,
-    "email" TEXT,
-    "emailVerified" DATETIME,
-    "phone" TEXT,
-    "phoneVerified" DATETIME,
-    "image" TEXT,
-    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    "updatedAt" DATETIME NOT NULL
-);
-
--- CreateTable
-CREATE TABLE "accounts" (
-    "id" TEXT NOT NULL PRIMARY KEY,
-    "user_id" TEXT NOT NULL,
-    "type" TEXT NOT NULL,
-    "provider" TEXT NOT NULL,
-    "provider_account_id" TEXT NOT NULL,
-    "refresh_token" TEXT,
-    "access_token" TEXT,
-    "expires_at" INTEGER,
-    "token_type" TEXT,
-    "scope" TEXT,
-    "id_token" TEXT,
-    "session_state" TEXT,
-    CONSTRAINT "accounts_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
-);
-
--- CreateTable
-CREATE TABLE "sessions" (
-    "id" TEXT NOT NULL PRIMARY KEY,
-    "session_token" TEXT NOT NULL,
-    "user_id" TEXT NOT NULL,
-    "expires" DATETIME NOT NULL,
-    CONSTRAINT "sessions_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
-);
-
--- CreateTable
-CREATE TABLE "posts" (
-    "id" TEXT NOT NULL PRIMARY KEY,
-    "title" TEXT NOT NULL,
-    "content" TEXT NOT NULL,
-    "user_id" TEXT NOT NULL,
-    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    "updatedAt" DATETIME NOT NULL,
-    CONSTRAINT "posts_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
-);
-
--- CreateTable
-CREATE TABLE "comments" (
-    "id" TEXT NOT NULL PRIMARY KEY,
-    "content" TEXT NOT NULL,
-    "user_id" TEXT NOT NULL,
-    "post_id" TEXT NOT NULL,
-    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    "updatedAt" DATETIME NOT NULL,
-    CONSTRAINT "comments_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
-    CONSTRAINT "comments_post_id_fkey" FOREIGN KEY ("post_id") REFERENCES "posts" ("id") ON DELETE CASCADE ON UPDATE CASCADE
-);
-
--- CreateTable
-CREATE TABLE "verification_tokens" (
-    "identifier" TEXT NOT NULL,
-    "token" TEXT NOT NULL,
-    "expires" DATETIME NOT NULL
-);
-
--- CreateIndex
-CREATE UNIQUE INDEX "User_email_key" ON "User"("email");
-
--- CreateIndex
-CREATE UNIQUE INDEX "User_phone_key" ON "User"("phone");
-
--- CreateIndex
-CREATE UNIQUE INDEX "accounts_provider_provider_account_id_key" ON "accounts"("provider", "provider_account_id");
-
--- CreateIndex
-CREATE UNIQUE INDEX "sessions_session_token_key" ON "sessions"("session_token");
-
--- CreateIndex
-CREATE UNIQUE INDEX "verification_tokens_token_key" ON "verification_tokens"("token");
-
--- CreateIndex
-CREATE UNIQUE INDEX "verification_tokens_identifier_token_key" ON "verification_tokens"("identifier", "token");

backend/prisma/migrations/20260309031703_add_resources_posts/migration.sql

@@ -1,30 +0,0 @@
--- CreateTable
-CREATE TABLE "resources" (
-    "id" TEXT NOT NULL PRIMARY KEY,
-    "title" TEXT NOT NULL,
-    "description" TEXT,
-    "url" TEXT NOT NULL,
-    "icon" TEXT,
-    "category" TEXT,
-    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    "updatedAt" DATETIME NOT NULL
-);
-
--- RedefineTables
-PRAGMA defer_foreign_keys=ON;
-PRAGMA foreign_keys=OFF;
-CREATE TABLE "new_posts" (
-    "id" TEXT NOT NULL PRIMARY KEY,
-    "title" TEXT NOT NULL,
-    "content" TEXT NOT NULL,
-    "user_id" TEXT NOT NULL,
-    "published" BOOLEAN NOT NULL DEFAULT false,
-    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    "updatedAt" DATETIME NOT NULL,
-    CONSTRAINT "posts_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
-);
-INSERT INTO "new_posts" ("content", "createdAt", "id", "title", "updatedAt", "user_id") SELECT "content", "createdAt", "id", "title", "updatedAt", "user_id" FROM "posts";
-DROP TABLE "posts";
-ALTER TABLE "new_posts" RENAME TO "posts";
-PRAGMA foreign_keys=ON;
-PRAGMA defer_foreign_keys=OFF;

backend/prisma/migrations/migration_lock.toml

@@ -1,3 +0,0 @@
-# Please do not edit this file manually
-# It should be added in your version-control system (i.e. Git)
-provider = "sqlite"

backend/prisma/schema.prisma

@@ -2,14 +2,11 @@
 // learn more about it in the docs: https://pris.ly/d/prisma-schema
 
 generator client {
-  provider   = "prisma-client"
-  output     = "../src/generated/prisma"
-  engineType = "client"
-  runtime    = "bun"
+  provider = "prisma-client-js"
 }
 
 datasource db {
-  provider = "sqlite"
+  provider = "postgresql"
 }
 
 model User {
@@ -26,6 +23,8 @@ model User {
   sessions      Session[]
   posts         Post[]
   comments      Comment[]
+
+  @@map("users")
 }
 
 model Account {
@@ -41,7 +40,7 @@ model Account {
   scope              String?
   id_token           String?
   session_state      String?
-  user               User    @relation(fields: [userId], references: [id], onDelete: Cascade)
+  user      User    @relation(fields: [userId], references: [id], onDelete: Cascade)
 
   @@unique([provider, providerAccountId])
   @@map("accounts")