feat: add topic alias resolution APIs

tests/identity-db.test.ts

@@ -51,4 +51,41 @@ describe('IdentityDB topic and fact writes', () => {
     expect(typeScriptFacts).toHaveLength(1);
     expect(typeScriptFacts[0]?.statement).toBe('I have worked with TypeScript since 2025.');
   });
+
+  it('resolves alias names to a canonical topic', async () => {
+    await db.upsertTopic({
+      name: 'TypeScript',
+      category: 'entity',
+      granularity: 'concrete',
+    });
+
+    await db.addTopicAlias('TypeScript', 'TS');
+
+    const resolved = await db.resolveTopic('ts');
+    const aliases = await db.getTopicAliases('TypeScript');
+
+    expect(resolved?.name).toBe('TypeScript');
+    expect(aliases).toEqual(['TS']);
+  });
+
+  it('reuses the canonical topic when a fact is added through an alias', async () => {
+    await db.upsertTopic({
+      name: 'TypeScript',
+      category: 'entity',
+      granularity: 'concrete',
+    });
+
+    await db.addTopicAlias('TypeScript', 'TS');
+
+    await db.addFact({
+      statement: 'TS compiles to JavaScript.',
+      topics: [{ name: 'TS', category: 'entity', granularity: 'concrete' }],
+    });
+
+    const topics = await db.listTopics({ includeFacts: false });
+    const facts = await db.getTopicFacts('TypeScript');
+
+    expect(topics.map((topic) => topic.name)).toEqual(['TypeScript']);
+    expect(facts.map((fact) => fact.statement)).toEqual(['TS compiles to JavaScript.']);
+  });
 });