feat(napta): resolve project Members (real+active, role, sorted)

Filter user_project by project + simulated=false, include user, drop inactive
people, dedupe per user, map user_position -> Role, sort by last name.

backend/src/napta.ts

@@ -137,8 +137,68 @@ export async function fetchNaptaProjects(): Promise<Project[]> {
     .sort((a, b) => a.name.localeCompare(b.name))
 }
 
-// --- Members (implemented in Slice 2) ---
-
-export async function fetchNaptaProjectMembers(_projectId: string): Promise<Member[]> {
-  throw new Error("Napta member resolution not implemented yet (Slice 2)")
+// Prefer a flat `<name>_id` attribute, else the relationship's resource id.
+function relatedId(resource: JsonApiResource, name: string): string | null {
+  const flat = resource.attributes[`${name}_id`]
+  if (flat != null) return String(flat)
+  return relId(resource, name)
+}
+
+// --- Positions (Role lookup), cached for the process lifetime ---
+
+let positionMapCache: Map<string, string> | null = null
+
+async function getPositionMap(): Promise<Map<string, string>> {
+  if (positionMapCache) return positionMapCache
+  const { data } = await naptaGetAll("/user_position", {})
+  const map = new Map<string, string>()
+  for (const p of data) map.set(p.id, attr(p, "name"))
+  positionMapCache = map
+  return map
+}
+
+// --- Members ---
+
+export async function fetchNaptaProjectMembers(projectId: string): Promise<Member[]> {
+  const [{ data, included }, positions] = await Promise.all([
+    naptaGetAll("/user_project", {
+      // Real staffing on this Project only (drop simulated/forecast scenarios).
+      filters: [
+        { name: "project_id", op: "eq", val: projectId },
+        { name: "simulated", op: "eq", val: false },
+      ],
+      include: ["user"],
+    }),
+    getPositionMap(),
+  ])
+
+  const userById = new Map<string, JsonApiResource>()
+  for (const inc of included) {
+    if (inc.type === "user") userById.set(inc.id, inc)
+  }
+
+  // One Member per user, even if they have several assignments on the Project.
+  const byUserId = new Map<string, Member>()
+  for (const up of data) {
+    const userId = relatedId(up, "user")
+    if (!userId || byUserId.has(userId)) continue
+    const user = userById.get(userId)
+    if (!user) continue
+    if (user.attributes.active === false) continue // drop departed people
+    const positionId = relatedId(user, "user_position")
+    byUserId.set(userId, {
+      id: userId,
+      firstName: attr(user, "first_name"),
+      lastName: attr(user, "last_name"),
+      role: (positionId && positions.get(positionId)) || "",
+      email: attr(user, "email"),
+      imageUrl: null,
+      slackMatched: false,
+    })
+  }
+
+  return [...byUserId.values()].sort(
+    (a, b) =>
+      a.lastName.localeCompare(b.lastName) || a.firstName.localeCompare(b.firstName),
+  )
 }