feat: add progression readiness api

internal/httpapi/progression.go

@@ -0,0 +1,46 @@
+package httpapi
+
+import (
+	"errors"
+	"net/http"
+
+	"tutor/internal/learnermemory"
+)
+
+func (h Handler) getReadinessMap(w http.ResponseWriter, r *http.Request) {
+	if h.progress == nil {
+		writeError(w, http.StatusNotFound, "progression not configured")
+		return
+	}
+
+	readiness, err := h.progress.ReadinessMap(r.PathValue("userID"))
+	if errors.Is(err, learnermemory.ErrProfileNotFound) {
+		writeError(w, http.StatusNotFound, "learner memory not found")
+		return
+	}
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusOK, readiness)
+}
+
+func (h Handler) getNextChallenge(w http.ResponseWriter, r *http.Request) {
+	if h.progress == nil {
+		writeError(w, http.StatusNotFound, "progression not configured")
+		return
+	}
+
+	challenge, err := h.progress.NextChallenge(r.PathValue("userID"))
+	if errors.Is(err, learnermemory.ErrProfileNotFound) {
+		writeError(w, http.StatusNotFound, "learner memory not found")
+		return
+	}
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusOK, challenge)
+}