refactor: replace raw SQL with repository interfaces in entranceserver and API server

Extract all direct database calls from entranceserver (2 calls) and
API server (17 calls) into typed repository interfaces with PostgreSQL
implementations, matching the pattern established in signserver and
channelserver.

Entranceserver: EntranceServerRepo, EntranceSessionRepo
API server: APIUserRepo, APICharacterRepo, APISessionRepo

Also fix the 3 remaining fmt.Sprintf calls inside logger invocations
in handlers_commands.go and handlers_stage.go, replacing them with
structured zap fields.

Unskip 5 TestNewAuthData* tests that previously required a real
database — they now run with mock repos.

server/api/repo_mocks_test.go

@@ -0,0 +1,124 @@
+package api
+
+import (
+	"context"
+	"time"
+)
+
+// mockAPIUserRepo implements APIUserRepo for testing.
+type mockAPIUserRepo struct {
+	registerID     uint32
+	registerRights uint32
+	registerErr    error
+
+	credentialsID       uint32
+	credentialsPassword string
+	credentialsRights   uint32
+	credentialsErr      error
+
+	lastLogin    time.Time
+	lastLoginErr error
+
+	returnExpiry    time.Time
+	returnExpiryErr error
+
+	updateReturnExpiryErr error
+	updateLastLoginErr    error
+}
+
+func (m *mockAPIUserRepo) Register(_ context.Context, _, _ string, _ time.Time) (uint32, uint32, error) {
+	return m.registerID, m.registerRights, m.registerErr
+}
+
+func (m *mockAPIUserRepo) GetCredentials(_ context.Context, _ string) (uint32, string, uint32, error) {
+	return m.credentialsID, m.credentialsPassword, m.credentialsRights, m.credentialsErr
+}
+
+func (m *mockAPIUserRepo) GetLastLogin(_ uint32) (time.Time, error) {
+	return m.lastLogin, m.lastLoginErr
+}
+
+func (m *mockAPIUserRepo) GetReturnExpiry(_ uint32) (time.Time, error) {
+	return m.returnExpiry, m.returnExpiryErr
+}
+
+func (m *mockAPIUserRepo) UpdateReturnExpiry(_ uint32, _ time.Time) error {
+	return m.updateReturnExpiryErr
+}
+
+func (m *mockAPIUserRepo) UpdateLastLogin(_ uint32, _ time.Time) error {
+	return m.updateLastLoginErr
+}
+
+// mockAPICharacterRepo implements APICharacterRepo for testing.
+type mockAPICharacterRepo struct {
+	newCharacter    Character
+	newCharacterErr error
+
+	countForUser    int
+	countForUserErr error
+
+	createChar    Character
+	createCharErr error
+
+	isNewResult bool
+	isNewErr    error
+
+	hardDeleteErr error
+	softDeleteErr error
+
+	characters    []Character
+	charactersErr error
+
+	exportResult map[string]interface{}
+	exportErr    error
+}
+
+func (m *mockAPICharacterRepo) GetNewCharacter(_ context.Context, _ uint32) (Character, error) {
+	return m.newCharacter, m.newCharacterErr
+}
+
+func (m *mockAPICharacterRepo) CountForUser(_ context.Context, _ uint32) (int, error) {
+	return m.countForUser, m.countForUserErr
+}
+
+func (m *mockAPICharacterRepo) Create(_ context.Context, _ uint32, _ uint32) (Character, error) {
+	return m.createChar, m.createCharErr
+}
+
+func (m *mockAPICharacterRepo) IsNew(_ uint32) (bool, error) {
+	return m.isNewResult, m.isNewErr
+}
+
+func (m *mockAPICharacterRepo) HardDelete(_ uint32) error {
+	return m.hardDeleteErr
+}
+
+func (m *mockAPICharacterRepo) SoftDelete(_ uint32) error {
+	return m.softDeleteErr
+}
+
+func (m *mockAPICharacterRepo) GetForUser(_ context.Context, _ uint32) ([]Character, error) {
+	return m.characters, m.charactersErr
+}
+
+func (m *mockAPICharacterRepo) ExportSave(_ context.Context, _, _ uint32) (map[string]interface{}, error) {
+	return m.exportResult, m.exportErr
+}
+
+// mockAPISessionRepo implements APISessionRepo for testing.
+type mockAPISessionRepo struct {
+	createTokenID  uint32
+	createTokenErr error
+
+	userID    uint32
+	userIDErr error
+}
+
+func (m *mockAPISessionRepo) CreateToken(_ context.Context, _ uint32, _ string) (uint32, error) {
+	return m.createTokenID, m.createTokenErr
+}
+
+func (m *mockAPISessionRepo) GetUserIDByToken(_ context.Context, _ string) (uint32, error) {
+	return m.userID, m.userIDErr
+}