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/misc.py

@@ -65,13 +65,18 @@ def api_courses(b: CookiesIn):
     if not b.cookies:
         return JSONResponse({"ok": False, "code": "no_cookie",
                              "error": "本机没有该账号的会话 cookie，请先点「登录」"}, status_code=200)
-    s = new_session(b.cookies)
+    pf = registry.get(b.platform)
+    if pf is None or pf.list_courses is None:
+        return JSONResponse({"ok": False, "code": "no_platform",
+                             "error": "平台「%s」还没有实现刷新课程，请先在 platforms/ 里补上"
+                                      % b.platform}, status_code=200)
+    s = (pf.session or new_session)(b.cookies)
     if not s.cookies:
         return JSONResponse({"ok": False, "code": "no_cookie",
                              "error": "保存的 cookie 全部被过滤（domain 不含 dgjy），请重新登录"},
                             status_code=200)
     try:
-        courses = scrape_courses(s)
+        courses = pf.list_courses(s)
     except SessionExpired as e:
         return JSONResponse({"ok": False, "code": "session_expired", "error": str(e)[:300]}, status_code=200)
     except Exception as e:
@@ -81,21 +86,25 @@ def api_courses(b: CookiesIn):
                              "error": "登录态有效，但该账号名下三个板块（在学/助学/督学）"
                                       "的进行中、未开始、已结束里都没有课程"}, status_code=200)
     try:
-        user = whoami(fetch_admin(s))
+        user = pf.profile(s) if pf.profile else ""
     except Exception:
         user = ""
     return {"ok": True, "courses": courses, "user": user,
             "in_study": len([c for c in courses if c["in_study"]]),
-            # 补 jspx 会话时 cookie 会换新（JSESSIONID/route），回传让前端写回 IndexedDB
-            "cookies": dump_cookies(s)}
+            # 补 jspx 会话时 cookie 会换新（JSESSIONID/route），回传让前端写回
+            "cookies": (pf.dump_cookies or dump_cookies)(s)}
 
 
 @app.post("/api/discover")
 def api_discover(b: DiscoverIn):
-    s = new_session(b.cookies)
+    pf = registry.get(b.platform)
+    if pf is None or pf.discover is None:
+        return JSONResponse({"ok": False, "code": "no_platform",
+                             "error": "平台「%s」还没有实现课程发现" % b.platform}, status_code=200)
+    s = (pf.session or new_session)(b.cookies)
     try:
-        d = discover(s, b.plan_id, b.project_id, b.name)
-        return {"ok": True, **d, "cookies": dump_cookies(s)}
+        d = pf.discover(s, b.plan_id, b.project_id, b.name)
+        return {"ok": True, **d, "cookies": (pf.dump_cookies or dump_cookies)(s)}
     except Exception as e:
         return JSONResponse({"ok": False, "error": str(e)[:300]}, status_code=200)