feat: Add recovery code MFA support (#9954)

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One-time recovery codes are a common multi-factor authentication (MFA)
backup method, letting users access their account if they lose other MFA
devices. Support for recovery codes can also reduce support burden for
users locked out of their accounts and provide a more secure and
reliable form of verification than security questions.

# Which Problems Are Solved

Zitadel currently lacks support for recovery codes.

# How the Problems Are Solved

This PR partially addresses recovery code support in Zitadel.
Importantly, it adds recovery codes as a new 2FA `Factor` and an
additional `Check` type for the Session API.

```
Example recovery code flow:

1. User generates N new recovery codes using `POST /v2/users/{user_id}/recovery_codes`
2. Zitadel hashes and stores these codes and returns the un-hashed codes in the response
3. User creates new session with an additional check: `recoveryCode`
4. Code is checked against hash and, if valid, cannot be used again
5. User attempts to adds N more codes using the same endpoint 
6. If `remaining_codes + N <= RecoveryCodes->MaxCount` config value, then recovery codes are added in addition to original codes
7. User can remove all recovery codes using `DEL /v2/users/:userId/recovery_codes` 
```
This PR adds: 
- [x] Session recovery_code check support on `POST+PATCH /v2/sessions`
endpoints
- [x] Adds `mfa_recovery_code_checked_at` column (default null) to
`projections.sessions8` table
- [x] Support for `SECOND_FACTOR_TYPE_RECOVERY_CODES` as available 2FA
method on login policy
- [x] Support for importing recovery codes in /import code

Missing, will _not_ implement in this PR:
- [ ] Admin console support for displaying Recovery Code settings for
user(s)
- [ ] Zitadel Typescript login support for recovery codes 

TODO: 
- [x] Additional unit and integration tests
- [x] Error translations

# Additional Changes

None

# Additional Context

- Closes #6898

---------

Co-authored-by: Livio Spring <[email protected]>

internal/command/session_model.go

@@ -41,28 +41,28 @@ func (p *WebAuthNChallengeModel) WebAuthNLogin(human *domain.Human, credentialAs
 type SessionWriteModel struct {
 	eventstore.WriteModel
 
-	TokenID              string
-	UserID               string
-	UserResourceOwner    string
-	PreferredLanguage    *language.Tag
-	UserCheckedAt        time.Time
-	PasswordCheckedAt    time.Time
-	IntentCheckedAt      time.Time
-	WebAuthNCheckedAt    time.Time
-	TOTPCheckedAt        time.Time
-	OTPSMSCheckedAt      time.Time
-	OTPEmailCheckedAt    time.Time
-	WebAuthNUserVerified bool
-	Metadata             map[string][]byte
-	State                domain.SessionState
-	UserAgent            *domain.UserAgent
-	Expiration           time.Time
+	TokenID               string
+	UserID                string
+	UserResourceOwner     string
+	PreferredLanguage     *language.Tag
+	UserCheckedAt         time.Time
+	PasswordCheckedAt     time.Time
+	IntentCheckedAt       time.Time
+	WebAuthNCheckedAt     time.Time
+	TOTPCheckedAt         time.Time
+	OTPSMSCheckedAt       time.Time
+	OTPEmailCheckedAt     time.Time
+	RecoveryCodeCheckedAt time.Time
+	WebAuthNUserVerified  bool
+	Metadata              map[string][]byte
+	State                 domain.SessionState
+	UserAgent             *domain.UserAgent
+	Expiration            time.Time
 
 	WebAuthNChallenge     *WebAuthNChallengeModel
 	OTPSMSCodeChallenge   *OTPCode
 	OTPEmailCodeChallenge *OTPCode
-
-	aggregate *eventstore.Aggregate
+	aggregate             *eventstore.Aggregate
 }
 
 func NewSessionWriteModel(sessionID string, instanceID string) *SessionWriteModel {
@@ -108,6 +108,8 @@ func (wm *SessionWriteModel) Reduce() error {
 			wm.reduceLifetimeSet(e)
 		case *session.TerminateEvent:
 			wm.reduceTerminate()
+		case *session.RecoveryCodeCheckedEvent:
+			wm.reduceRecoveryCodeChecked(e)
 		}
 	}
 	return wm.WriteModel.Reduce()
@@ -131,6 +133,7 @@ func (wm *SessionWriteModel) Query() *eventstore.SearchQueryBuilder {
 			session.OTPSMSCheckedType,
 			session.OTPEmailChallengedType,
 			session.OTPEmailCheckedType,
+			session.RecoveryCodeCheckedType,
 			session.TokenSetType,
 			session.MetadataSetType,
 			session.LifetimeSetType,
@@ -227,6 +230,10 @@ func (wm *SessionWriteModel) reduceTerminate() {
 	wm.State = domain.SessionStateTerminated
 }
 
+func (wm *SessionWriteModel) reduceRecoveryCodeChecked(e *session.RecoveryCodeCheckedEvent) {
+	wm.RecoveryCodeCheckedAt = e.CheckedAt
+}
+
 // AuthenticationTime returns the time the user authenticated using the latest time of all checks
 func (wm *SessionWriteModel) AuthenticationTime() time.Time {
 	var authTime time.Time
@@ -270,6 +277,9 @@ func (wm *SessionWriteModel) AuthMethodTypes() []domain.UserAuthMethodType {
 	if !wm.OTPEmailCheckedAt.IsZero() {
 		types = append(types, domain.UserAuthMethodTypeOTPEmail)
 	}
+	if !wm.RecoveryCodeCheckedAt.IsZero() {
+		types = append(types, domain.UserAuthMethodTypeRecoveryCode)
+	}
 	return types
 }