feat: 添加账号支持选择学习平台

账号新增 platform 字段，登录/刷新课程/发现课程按平台分发；同时把 JS 脚本收进 script/（目录规范调整）。

src/study_tool/routes/accounts.py

@@ -1,13 +1,16 @@
 """账号 / 登录 / 登录记录接口。"""
 import time
 
+from fastapi.responses import JSONResponse
+
 from study_tool.webapp import app
 
 from study_tool import store
 from study_tool.config import *
 from study_tool.models import *
+from study_tool.platforms import registry
 from study_tool.platforms.jspx import *
-from study_tool.runtime import log
+from study_tool.runtime import RUNS, RUNS_LOCK, log
 
 def _log_login(username, ok, code, error, elapsed, stage=""):
     """每次登录尝试：统一日志 + login_log 表（登录记录页用）。"""
@@ -37,8 +40,14 @@ def api_login(b: LoginIn):
         _log_login(username or b.account_id, False, "no_credential", err, time.time() - t0,
                    "LoginIn")
         return JSONResponse({"ok": False, "code": "no_credential", "error": err}, status_code=200)
+    pf = registry.get((acc or {}).get("platform") or b.platform)
+    if pf is None or pf.login is None:
+        err = "平台「%s」还没有实现登录，请换一个平台或先在 platforms/ 里补上实现" % (
+            (acc or {}).get("platform") or b.platform)
+        _log_login(username, False, "no_platform", err, time.time() - t0, "LoginIn")
+        return JSONResponse({"ok": False, "code": "no_platform", "error": err}, status_code=200)
     try:
-        s, user = login(username, password)
+        s, user = pf.login(username, password)
     except Exception as e:
         err = str(e)[:300]
         _log_login(username, False, "login_failed", err, time.time() - t0, type(e).__name__)
@@ -49,10 +58,10 @@ def api_login(b: LoginIn):
         return JSONResponse({"ok": False, "code": "login_failed", "error": err}, status_code=200)
     warn = ""
     try:
-        courses = scrape_courses(s)
+        courses = pf.list_courses(s) if pf.list_courses else []
     except Exception as e:
         courses, warn = [], str(e)[:200]
-    cookies = dump_cookies(s)
+    cookies = (pf.dump_cookies or dump_cookies)(s)
     _log_login(username, True, "ok", warn, time.time() - t0, "user=%s" % user)
     if acc:
         store.account_save_login(acc["id"], user, cookies, courses)