feat: add commands for managing organizations and users

Introduce `AddUserToOrganization`, `RemoveAPIKey`, and 
`RemoveOrganization` commands to enhance organization 
management. Implement validation for user addition and 
API key removal. Update GraphQL schema to support new 
mutations and add caching for the new events, ensuring 
that organizations and their relationships are accurately 
represented in the cache.

domain/commands_test.go

@@ -464,3 +464,114 @@ func TestUpdateSubGraph_Event(t *testing.T) {
 	assert.Equal(t, "type Query { hello: String }", subGraphEvent.Sdl)
 	assert.Equal(t, "user@example.com", subGraphEvent.Initiator)
 }
+
+// RemoveAPIKey tests
+
+func TestRemoveAPIKey_Validate_Success(t *testing.T) {
+	cmd := RemoveAPIKey{
+		KeyName:   "production-key",
+		Initiator: "user@example.com",
+	}
+
+	org := &Organization{
+		BaseAggregate: eventsourced.BaseAggregateFromString("org-123"),
+		APIKeys: []APIKey{
+			{
+				Name: "production-key",
+				Key:  "hashed-key",
+			},
+		},
+	}
+
+	err := cmd.Validate(context.Background(), org)
+	assert.NoError(t, err)
+}
+
+func TestRemoveAPIKey_Validate_OrganizationNotExists(t *testing.T) {
+	cmd := RemoveAPIKey{
+		KeyName:   "production-key",
+		Initiator: "user@example.com",
+	}
+
+	org := &Organization{} // No identity means it doesn't exist
+	err := cmd.Validate(context.Background(), org)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "does not exist")
+}
+
+func TestRemoveAPIKey_Validate_KeyNotFound(t *testing.T) {
+	cmd := RemoveAPIKey{
+		KeyName:   "non-existent-key",
+		Initiator: "user@example.com",
+	}
+
+	org := &Organization{
+		BaseAggregate: eventsourced.BaseAggregateFromString("org-123"),
+		APIKeys: []APIKey{
+			{
+				Name: "production-key",
+				Key:  "hashed-key",
+			},
+		},
+	}
+
+	err := cmd.Validate(context.Background(), org)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "not found")
+	assert.Contains(t, err.Error(), "non-existent-key")
+}
+
+func TestRemoveAPIKey_Event(t *testing.T) {
+	cmd := RemoveAPIKey{
+		KeyName:   "production-key",
+		Initiator: "user@example.com",
+	}
+
+	event := cmd.Event(context.Background())
+	require.NotNil(t, event)
+
+	keyEvent, ok := event.(*APIKeyRemoved)
+	require.True(t, ok)
+	assert.Equal(t, "production-key", keyEvent.KeyName)
+	assert.Equal(t, "user@example.com", keyEvent.Initiator)
+}
+
+// RemoveOrganization tests
+
+func TestRemoveOrganization_Validate_Success(t *testing.T) {
+	cmd := RemoveOrganization{
+		Initiator: "user@example.com",
+	}
+
+	org := &Organization{
+		BaseAggregate: eventsourced.BaseAggregateFromString("org-123"),
+		Name:          "Test Org",
+	}
+
+	err := cmd.Validate(context.Background(), org)
+	assert.NoError(t, err)
+}
+
+func TestRemoveOrganization_Validate_OrganizationNotExists(t *testing.T) {
+	cmd := RemoveOrganization{
+		Initiator: "user@example.com",
+	}
+
+	org := &Organization{} // No identity means it doesn't exist
+	err := cmd.Validate(context.Background(), org)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "does not exist")
+}
+
+func TestRemoveOrganization_Event(t *testing.T) {
+	cmd := RemoveOrganization{
+		Initiator: "user@example.com",
+	}
+
+	event := cmd.Event(context.Background())
+	require.NotNil(t, event)
+
+	orgEvent, ok := event.(*OrganizationRemoved)
+	require.True(t, ok)
+	assert.Equal(t, "user@example.com", orgEvent.Initiator)
+}