Replace per-kind reclassify with a single global reclassify that respects manual and Race locks

Manual assignments are the user's definitive word and Race assignments come
from a hard Garmin fact (eventType.typeKey), not a retunable rule -- neither
is ever touched by reclassify again, and Race can no longer be set by hand
via the review queue. Adds an Activities page so this locked/unlocked status
is visible per workout, since Review Queue only ever showed unresolved items.

frontend/src/api/client.ts

@@ -1,5 +1,6 @@
 import type {
   Activity,
+  ActivityListItem,
   AuthResponse,
   KindAssignment,
   Profile,
@@ -46,7 +47,7 @@ export const api = {
     if (params?.to) q.set("to", params.to);
     if (params?.limit) q.set("limit", String(params.limit));
     const qs = q.toString();
-    return request<Activity[]>(`/api/activities/${qs ? `?${qs}` : ""}`);
+    return request<ActivityListItem[]>(`/api/activities/${qs ? `?${qs}` : ""}`);
   },
   getActivity: (id: number) =>
     request<{ activity: Activity; laps: unknown[]; assignment?: KindAssignment }>(`/api/activities/${id}`),
@@ -68,8 +69,10 @@ export const api = {
       expected_hr_zone?: number | null;
     },
   ) => request<WorkoutKind>(`/api/workout-kinds/${id}`, { method: "PUT", body: JSON.stringify(body) }),
-  reclassifyWorkoutKind: (id: number) =>
-    request<{ reclassified: number }>(`/api/workout-kinds/${id}/reclassify`, { method: "POST" }),
+
+  // Reclassifies every activity that isn't locked (manual assignments and
+  // Race assignments are never touched -- see handleReclassifyAll).
+  reclassifyAll: () => request<{ reclassified: number }>("/api/reclassify", { method: "POST" }),
 
   // Profile
   getProfile: () => request<Profile>("/api/profile"),