chore: 数据已迁到 SQLite，删掉 Postgres 迁移脚本、webpreview-db 服务和迁移文档

school 服务器以后要切换时，从 cdeb7c1 里找回（deploy.yaml 里写了）。
备份方法挪到 CLAUDE.md。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/deploy.yaml

@@ -18,7 +18,8 @@ jobs:
           - name: debian
             build_command: build
             remote_port: 22
-          # school 暂时停用，需要时恢复（并先按 docs/migrate-to-bun.md 切换那台服务器）
+          # school 暂时停用，需要时恢复。那台还没从 Postgres 迁到 SQLite：迁移脚本、webpreview-db 服务和
+          # 步骤文档已删除，从提交 cdeb7c1 里找回（git show cdeb7c1:docs/migrate-to-bun.md）
           # - name: school
           #   build_command: build:staging
           #   remote_port: 8822

CLAUDE.md

@@ -18,7 +18,7 @@ The backend was rewritten from Django in 2026-10 to cut memory use (~25 MB vs. 1
   - `src/routes/` — `account`, `tasks` (tutorial / challenge / creation), `files` (task assets + image upload), `submission`, `showcase` (mounted under `/submission/showcase`), `prompt`
   - `src/services/` — `score.ts` (rating weights super×0.5, admin×0.3, normal×0.2, then Bayesian smoothing with C=3 and zones), `gradebook.ts`, `llm.ts` (OpenAI-compatible streaming via fetch; DeepSeek default, ARK for doubao models), `classifier.ts` (Bloom-level L1–L6 prompt tagging, runs in background), `cascade.ts` (Django's CASCADE deletes, done by hand), `pyround.ts` (`pyRound`/`pySum` reproduce Python's `round()` and `sum()` so scores match the old system bit-for-bit)
   - `src/ws.ts` — `/ws/prompt/<task_id>/?token=<access_token>` (code generation chat) and `/ws/guidance/<task_id>/?token=...` (prompt coaching); messages per connection are processed serially; on disconnect the pending user message is deleted and the LLM request aborted
-  - `scripts/` — one-off CLIs: `migrate-from-postgres.ts`, `create-superuser.ts`, `classify-prompts.ts`, `recalculate-scores.ts`
+  - `scripts/` — one-off CLIs: `create-superuser.ts`, `classify-prompts.ts`, `recalculate-scores.ts`
   - Roles: `super`, `admin`, `normal`. Task model is multi-table: `task_task` + one of `task_tutorial` / `task_challenge` / `task_creation` (`task_ptr_id`)
 
 - **`client/`** — Vue 3 + TypeScript SPA built with **Vite**; Bun is the package manager and runtime (no Node/npm)
@@ -31,7 +31,7 @@ The backend was rewritten from Django in 2026-10 to cut memory use (~25 MB vs. 1
   - `src/pages/`, `src/components/` — user management uses `components/dashboard/UserFormModal.vue` (there is no Django Admin anymore)
 
 - **`Caddyfile`** — serves SPA from `build/` and `/media`, proxies `/api*` and `/ws*` to the backend
-- **`docker-compose.yaml`** — `webpreview-web` (Caddy) and `webpreview-api` (Bun); `webpreview-db` (Postgres) exists only under the `migrate` profile for the one-time data migration
+- **`docker-compose.yaml`** — `webpreview-web` (Caddy) and `webpreview-api` (Bun); the API reads the repo-root `.env` via `env_file` (`server/.env` is only for local dev). The one-time Postgres → SQLite migration (script, `webpreview-db` service, `docs/migrate-to-bun.md`) was removed after commit `cdeb7c1`; restore it from there if another server still needs the cutover
 - **`.github/workflows/deploy.yaml`** — on push to `main`: build client with Bun, rsync to server `build/`, then `git pull && docker compose up -d --build` on the server
 
 ## Development Commands
@@ -72,6 +72,7 @@ Frontend env vars used at build time: `PUBLIC_BASE_URL`, `PUBLIC_WS_URL`, `PUBLI
 docker compose up -d --build
 docker compose run --rm webpreview-api bun scripts/create-superuser.ts <username> <password>
 ```
+Back up production by copying `sqlite/` (or `sqlite3 sqlite/db.sqlite3 ".backup backup.sqlite3"`).
 
 ## Key Technical Details
 

docker-compose.yaml

@@ -23,16 +23,3 @@ services:
       - ./sqlite:/app/data
       - ./media:/app/media
     restart: unless-stopped
-
-  # 只在从旧版 Postgres 迁移数据时使用：
-  #   docker compose --profile migrate up -d webpreview-db
-  #   docker compose run --rm webpreview-api bun scripts/migrate-from-postgres.ts
-  webpreview-db:
-    image: postgres:17-alpine
-    container_name: webpreview-db
-    profiles: ["migrate"]
-    volumes:
-      - ./data:/var/lib/postgresql/data
-    env_file:
-      - .env
-    restart: "no"

docs/migrate-to-bun.md

@@ -1,75 +0,0 @@
-# 服务器切换到 Bun 后端（一次性）
-
-后端从 Django + Postgres + Redis 换成了 Bun + SQLite，前后端也合并成了一个仓库
-（`git.xuyue.cc:xuyue/web.git` / `github.com/yuetsh/web`）。
-每台服务器（debian、school）都要按下面的步骤做一次，之后 push 到 `main` 就会自动部署。
-
-切换时所有人需要重新登录一次（旧的登录会话在 Redis 里，不迁移）。密码不受影响。
-
-## 0. GitHub 仓库设置
-
-在 `yuetsh/web` 的 Settings → Secrets and variables → Actions 里添加和旧仓库一样的 `KEY`、`HOST`。
-
-## 1. 备份
-
-```bash
-cd /root/WebPreview
-docker compose exec webpreview-db sh -c 'pg_dump -U "$POSTGRES_USER" "$POSTGRES_DB"' > /root/webpreview-$(date +%F).sql
-```
-
-`data/`（Postgres 数据目录）在整个过程中不会被修改，出问题可以随时回退。
-
-## 2. 把目录变成新仓库的 clone
-
-```bash
-cd /root/WebPreview
-git init -b main
-git remote add origin git@git.xuyue.cc:xuyue/web.git
-git fetch origin
-git reset origin/main      # 只建立 git 记录，不改动现有文件
-git checkout -- .          # 用仓库里的 docker-compose.yaml、Caddyfile 等覆盖旧文件
-mv api /root/webpreview-api-old   # 旧的 Django 后端，确认没问题后可删
-git status                 # 应该是干净的（.env、data/、build/、media/ 都被忽略）
-```
-
-## 3. 迁移数据（Postgres → SQLite）
-
-找一个没人用的时间做，先停掉旧后端，避免迁移期间有新数据写进 Postgres：
-
-```bash
-docker stop webpreview-api
-docker compose --profile migrate up -d webpreview-db     # 旧库本来就在运行的话不会有变化
-docker compose build webpreview-api
-docker compose run --rm --no-deps webpreview-api bun scripts/migrate-from-postgres.ts
-```
-
-脚本会逐表打印行数并做外键检查，最后输出 `导入完成` 才算成功。数据库文件在 `./sqlite/db.sqlite3`。
-`.env` 里原有的 `POSTGRES_*` 变量就是脚本要用的，不需要改。
-
-## 4. 启动新服务
-
-```bash
-docker compose up -d --remove-orphans      # 启动 Caddy + Bun，顺带删掉不再需要的 Redis 容器
-docker compose --profile migrate stop webpreview-db
-docker stats --no-stream                   # webpreview-api 应该在几十 MB
-```
-
-打开网站登录确认一下。之后就可以 `docker compose --profile migrate rm webpreview-db`，
-`data/` 目录建议留一段时间再删（属主是容器里的 postgres 用户，需要 root 才能删）。
-
-## 回退
-
-```bash
-docker compose down
-mv /root/webpreview-api-old api
-git show 47d4679:docker-compose.yaml > docker-compose.yaml
-git show 47d4679:Caddyfile > Caddyfile
-docker compose up -d --build
-```
-
-## 以后的日常操作
-
-- 部署：push 到 `main`，GitHub Actions 会构建前端并在服务器上 `git pull && docker compose up -d --build`
-- 新建超级管理员：`docker compose exec webpreview-api bun scripts/create-superuser.ts <用户名> <密码>`
-- 补标注提示词层级：`docker compose exec webpreview-api bun scripts/classify-prompts.ts`
-- 备份：复制 `sqlite/` 目录即可（或 `sqlite3 sqlite/db.sqlite3 ".backup backup.sqlite3"`）

server/scripts/migrate-from-postgres.ts

@@ -1,134 +0,0 @@
-/**
- * 把旧 Django 项目的 Postgres 数据导入 SQLite（一次性迁移）。
- *
- *   POSTGRES_HOST=... POSTGRES_DB=... POSTGRES_USER=... POSTGRES_PASSWORD=... \
- *     bun scripts/migrate-from-postgres.ts [--force]
- *
- * 目标库为 DB_PATH（默认 data/db.sqlite3）。目标库已有数据时需要 --force（会先清空）。
- * 会话不迁移，所有人需要重新登录一次。
- */
-import { SQL } from "bun"
-import { config } from "../src/config"
-import { db } from "../src/db"
-
-// 按外键依赖顺序
-const TABLES = [
-  "account_user",
-  "task_task",
-  "task_tutorial",
-  "task_challenge",
-  "task_creation",
-  "task_taskasset",
-  "submission_submission",
-  "submission_rating",
-  "submission_award",
-  "submission_submissionaward",
-  "prompt_conversation",
-  "prompt_message",
-]
-
-const force = process.argv.includes("--force")
-const env = process.env
-for (const key of ["POSTGRES_HOST", "POSTGRES_DB", "POSTGRES_USER", "POSTGRES_PASSWORD"]) {
-  if (!env[key]) {
-    console.error(`缺少环境变量 ${key}`)
-    process.exit(1)
-  }
-}
-
-const pg = new SQL({
-  hostname: env.POSTGRES_HOST,
-  port: Number(env.POSTGRES_PORT ?? 5432),
-  database: env.POSTGRES_DB,
-  username: env.POSTGRES_USER,
-  password: env.POSTGRES_PASSWORD,
-})
-
-const existing = db.query(`SELECT COUNT(*) AS n FROM account_user`).get() as { n: number }
-if (existing.n > 0 && !force) {
-  console.error(`目标库 ${config.dbPath} 已有数据，加 --force 会清空后重新导入`)
-  process.exit(1)
-}
-
-const quote = (name: string) => `"${name.replaceAll('"', '""')}"`
-
-// 按 Postgres 的列类型转换成 Django 在 SQLite 中的存储格式
-function selectExpr(column: string, pgType: string) {
-  const c = quote(column)
-  switch (pgType) {
-    case "timestamp with time zone":
-      return `to_char(${c} AT TIME ZONE 'UTC', 'YYYY-MM-DD HH24:MI:SS.US') AS ${c}`
-    case "timestamp without time zone":
-      return `to_char(${c}, 'YYYY-MM-DD HH24:MI:SS.US') AS ${c}`
-    case "uuid":
-      return `replace(${c}::text, '-', '') AS ${c}`
-    case "boolean":
-      return `${c}::int AS ${c}`
-    case "bigint":
-      return `${c}::text AS ${c}`
-    default:
-      return c
-  }
-}
-
-const counts: Record<string, number> = {}
-const rowsByTable: Record<string, Record<string, unknown>[]> = {}
-
-for (const table of TABLES) {
-  const sqliteColumns = (db.query(`PRAGMA table_info(${quote(table)})`).all() as { name: string }[]).map(
-    (c) => c.name,
-  )
-  const pgColumns = await pg`
-    SELECT column_name, data_type FROM information_schema.columns
-    WHERE table_schema = 'public' AND table_name = ${table}`
-  if (!pgColumns.length) throw new Error(`Postgres 中没有表 ${table}`)
-  const pgTypes = new Map<string, string>(pgColumns.map((c: any) => [c.column_name, c.data_type]))
-  const missing = sqliteColumns.filter((c) => !pgTypes.has(c))
-  if (missing.length) throw new Error(`Postgres 表 ${table} 缺少列：${missing.join(", ")}`)
-
-  const select = sqliteColumns.map((c) => selectExpr(c, pgTypes.get(c)!)).join(", ")
-  const rows: Record<string, unknown>[] = await pg.unsafe(`SELECT ${select} FROM ${quote(table)}`)
-  for (const row of rows) {
-    for (const c of sqliteColumns) {
-      if (pgTypes.get(c) === "bigint" && row[c] !== null) row[c] = Number(row[c])
-    }
-  }
-  rowsByTable[table] = rows
-  console.log(`读取 ${table}: ${rows.length} 行`)
-}
-await pg.close()
-
-db.transaction(() => {
-  db.run("PRAGMA defer_foreign_keys = ON")
-  for (const table of [...TABLES].reverse()) db.run(`DELETE FROM ${quote(table)}`)
-  db.run(`DELETE FROM auth_refresh_token`)
-  for (const table of TABLES) {
-    const rows = rowsByTable[table]!
-    if (!rows.length) {
-      counts[table] = 0
-      continue
-    }
-    const columns = Object.keys(rows[0]!)
-    const insert = db.prepare(
-      `INSERT INTO ${quote(table)} (${columns.map(quote).join(", ")})
-       VALUES (${columns.map((c) => "$" + c).join(", ")})`,
-    )
-    for (const row of rows) insert.run(row as any)
-    counts[table] = rows.length
-  }
-})()
-
-// 校验
-let ok = true
-for (const table of TABLES) {
-  const n = (db.query(`SELECT COUNT(*) AS n FROM ${quote(table)}`).get() as { n: number }).n
-  if (n !== counts[table]) ok = false
-  console.log(`${n === counts[table] ? "✓" : "✗"} ${table}: ${n}`)
-}
-const fk = db.query(`PRAGMA foreign_key_check`).all()
-if (fk.length) {
-  ok = false
-  console.error("外键检查失败：", fk.slice(0, 10))
-}
-console.log(ok ? `\n导入完成：${config.dbPath}` : "\n导入有问题，请检查上面的输出")
-process.exit(ok ? 0 : 1)