feat(backend): implement HTTP API, auth, chat, and admin surfaces

Expose learning, registration controls, mentor chat, realtime WebSocket, and staff administration.

backend/internal/api/learning.go

@@ -0,0 +1,42 @@
+package api
+
+import (
+	"net/http"
+
+	"pargar/backend/internal/observability"
+)
+
+func (s *Server) handleLearningOverview(w http.ResponseWriter, r *http.Request) {
+	ctx, span := observability.StartSpan(r.Context(), "admin.learning.overview")
+	defer span.End()
+	o, err := s.store.LearningOverview(ctx)
+	if err != nil {
+		writeErr(w, http.StatusInternalServerError, "بارگذاری نمای یادگیری ممکن نشد")
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"overview": o})
+}
+
+func (s *Server) handleLearningStudents(w http.ResponseWriter, r *http.Request) {
+	ctx, span := observability.StartSpan(r.Context(), "admin.learning.students")
+	defer span.End()
+	q := r.URL.Query().Get("q")
+	rows, err := s.store.ListStudentLearning(ctx, q)
+	if err != nil {
+		writeErr(w, http.StatusInternalServerError, "بارگذاری فهرست هنرجویان ممکن نشد")
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"students": rows})
+}
+
+func (s *Server) handleUserLearning(w http.ResponseWriter, r *http.Request) {
+	ctx, span := observability.StartSpan(r.Context(), "admin.learning.user")
+	defer span.End()
+	id := routeID(r, "id")
+	detail, err := s.store.UserLearningDetail(ctx, id)
+	if err != nil {
+		writeErr(w, http.StatusNotFound, "کاربر پیدا نشد")
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"learning": detail})
+}