feat(renown): add the Renown power-curve table and reputation-rank resolver

apps/api/src/reputation/reputation-rank.spec.ts

@@ -0,0 +1,33 @@
+import { resolveReputationRank } from './reputation-rank';
+
+describe('resolveReputationRank', () => {
+  it('resolves 0 reputation to Stranger with a next threshold of 100', () => {
+    expect(resolveReputationRank(0)).toEqual({
+      key: 'STRANGER',
+      label: 'Fremder',
+      threshold: 0,
+      nextThreshold: 100,
+    });
+  });
+
+  it('resolves exactly at a threshold to that rank, not the one below', () => {
+    expect(resolveReputationRank(100).key).toBe('TOLERATED');
+    expect(resolveReputationRank(99).key).toBe('STRANGER');
+  });
+
+  it('resolves every documented threshold to its exact rank', () => {
+    expect(resolveReputationRank(250).key).toBe('KNOWN');
+    expect(resolveReputationRank(500).key).toBe('RECOGNIZED');
+    expect(resolveReputationRank(800).key).toBe('TRUSTED');
+    expect(resolveReputationRank(1200).key).toBe('ESTEEMED');
+  });
+
+  it('has no next threshold once at the top rank', () => {
+    expect(resolveReputationRank(1200).nextThreshold).toBeNull();
+    expect(resolveReputationRank(50_000).nextThreshold).toBeNull();
+  });
+
+  it('reports the correct nextThreshold mid-range', () => {
+    expect(resolveReputationRank(300).nextThreshold).toBe(500);
+  });
+});