refactor: establish standalone application boundary

app/backend/features/mentor/routes.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+import json
+from datetime import date
+from http import HTTPStatus
+from urllib.parse import parse_qs
+
+
+class MentorRoutesMixin:
+    def _handle_mentor_get(self, parsed) -> bool:
+        if parsed.path == "/api/mentors/setup":
+            query = parse_qs(parsed.query)
+            trade_date = query.get("trade_date", [date.today().isoformat()])[0]
+            try:
+                self.send_json(self.application_service.mentor_setup(trade_date))
+            except ValueError as exc:
+                self.send_json({"error": str(exc)}, HTTPStatus.BAD_REQUEST)
+            return True
+        if parsed.path == "/api/mentors/messages":
+            query = parse_qs(parsed.query)
+            try:
+                self.send_json(
+                    {
+                        "items": self.application_service.mentor_messages(
+                            query.get("mentor_id", [""])[0],
+                            query.get("trade_date", [date.today().isoformat()])[0],
+                        )
+                    }
+                )
+            except ValueError as exc:
+                self.send_json({"error": str(exc)}, HTTPStatus.BAD_REQUEST)
+            return True
+        return False
+
+    def _handle_mentor_post(self, parsed) -> bool:
+        if parsed.path == "/api/mentors/preferences":
+            try:
+                result = self.application_service.save_mentor_preferences(self.read_json_body())
+                self.send_json({"ok": True, **result})
+            except (ValueError, json.JSONDecodeError) as exc:
+                self.send_json({"error": str(exc)}, HTTPStatus.BAD_REQUEST)
+            return True
+        return False
+
+    def _handle_mentor_delete(self, parsed) -> bool:
+        if parsed.path == "/api/mentors/messages":
+            query = parse_qs(parsed.query)
+            try:
+                deleted = self.application_service.clear_mentor_messages(
+                    query.get("mentor_id", [""])[0],
+                    query.get("trade_date", [date.today().isoformat()])[0],
+                )
+                self.send_json({"ok": True, "deleted": deleted})
+            except ValueError as exc:
+                self.send_json({"error": str(exc)}, HTTPStatus.BAD_REQUEST)
+            return True
+        return False