Fix course lookup in StaticDataLayerProvider by courseId

The provider was storing courses by dependency name (e.g., '@skuilder/course-<id>')
but getCourseDB() was looking them up by raw courseId. This caused 'Course not found'
errors when trying to access courses in static mode.

Now extracts courseId from manifest and uses it as the map key for both
courseUnpackers and manifests, ensuring consistent lookup.

Author: claude

packages/db/src/impl/static/StaticDataLayerProvider.ts

@@ -70,12 +70,18 @@ export class StaticDataLayerProvider implements DataLayerProvider {
             throw new Error(`Failed to fetch final content manifest for ${courseName} at ${finalManifestUrl}`);
           }
           const finalManifest = await finalManifestResponse.json();
-          
-          this.manifests[courseName] = finalManifest;
+
+          // Extract courseId from the manifest to use as the lookup key
+          const courseId = finalManifest.courseId || finalManifest.courseConfig?.courseID;
+          if (!courseId) {
+            throw new Error(`Course manifest for ${courseName} missing courseId`);
+          }
+
+          this.manifests[courseId] = finalManifest;
           const unpacker = new StaticDataUnpacker(finalManifest, baseUrl);
-          this.courseUnpackers.set(courseName, unpacker);
+          this.courseUnpackers.set(courseId, unpacker);
 
-          logger.info(`[StaticDataLayerProvider] Successfully resolved and prepared course: ${courseName}`);
+          logger.info(`[StaticDataLayerProvider] Successfully resolved and prepared course: ${courseName} (courseId: ${courseId})`);
         }
       } catch (e) {
         logger.error(`[StaticDataLayerProvider] Failed to resolve dependency ${courseName}:`, e);