refactor(nav): converge Login/SignUp/CreateProfile onto the majority navigateTo idiom (kills the C-NAV-002 shape)

Login/SignUp/CreateProfile drove navigation off a raw `success: Boolean` (and
`googleSuccess`) in a LaunchedEffect with no reset — the C-NAV-002 re-fire shape.
Correctness depended on a distant popUpTo; pressing system-back mid-onboarding
re-fired the stale flag and bounced the user forward.

The fix UNIFIES rather than fragments. Three nav patterns coexisted: 18 screens
on nullable `navigateTo` + `onNavigated()`, 3 on SharedFlow events, and these 3
on the raw boolean. Their own sibling — OnboardingViewModel — already uses the
nullable pattern, so these were the odd ones out within their own package.
Converted them to it: `navigateTo: String?` set on success (SignUp's two targets
collapse to one field — email→CreateProfile, google→Onboarding), cleared by
`onNavigated()` in the effect. Self-clearing means the flag cannot re-fire on
return, no matter the back stack — the loop is impossible by construction, not
by a remote popUpTo. Pattern count drops 3→2; no SharedFlow added (that would
have made a third variant — deliberately avoided).

Error handling unchanged and already unified: `uiState.error` + the house
snackbar (LaunchedEffect(state.error)). A failed op leaves navigateTo null and
sets error; success sets navigateTo once. The bare boolean never modeled the
failure path; this does.

Also deleted a stale exploration reference — `HomeViewModel.clearRecovery()`
does not exist in the tree (B1/HomeScreen needsRecovery stays as-is; it's
pop-safe via c636749c and touching it risks a keyless-Home frame).

Verified: unit suite green; Login navigateTo proven LIVE (sign-in routes
correctly through Onboarding, and system-back does not bounce back to Login —
the flag self-cleared). SignUp/CreateProfile are the identical conversion and
suite-green; exercising them live needs fresh accounts, avoided per standing
cost guidance. A Detekt rule enforcing the two blessed idioms comes in Tier 2.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/java/app/closer/ui/auth/LoginScreen.kt

@@ -70,8 +70,8 @@ fun LoginScreen(
     val context = LocalContext.current
     val scope = rememberCoroutineScope()
 
-    LaunchedEffect(state.success) {
+    LaunchedEffect(state.navigateTo) {
-        if (state.success) onNavigate(AppRoute.ONBOARDING)
+        state.navigateTo?.let { onNavigate(it); viewModel.onNavigated() }
     }
     LaunchedEffect(state.error) {
         state.error?.let { snackbar.showSnackbar(it); viewModel.dismissError() }

app/src/main/java/app/closer/ui/auth/LoginViewModel.kt

@@ -2,6 +2,7 @@ package app.closer.ui.auth
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import app.closer.core.navigation.AppRoute
 import app.closer.domain.repository.AuthRepository
 import app.closer.domain.usecase.GoogleProfileMerger
 import dagger.hilt.android.lifecycle.HiltViewModel
@@ -18,7 +19,9 @@ data class LoginUiState(
     val isPasswordVisible: Boolean = false,
     val isLoading: Boolean = false,
     val error: String? = null,
-    val success: Boolean = false
+    // Nullable one-shot nav target + onNavigated() reset — the majority idiom (OnboardingViewModel,
+    // 18 screens). Self-clearing, so returning to a stale Login entry can't re-fire (C-NAV-002 class).
+    val navigateTo: String? = null
 )
 
 @HiltViewModel
@@ -34,6 +37,7 @@ class LoginViewModel @Inject constructor(
     fun updatePassword(pw: String) = _uiState.update { it.copy(password = pw, error = null) }
     fun togglePasswordVisibility() = _uiState.update { it.copy(isPasswordVisible = !it.isPasswordVisible) }
     fun dismissError() = _uiState.update { it.copy(error = null) }
+    fun onNavigated() = _uiState.update { it.copy(navigateTo = null) }
 
     fun signIn() {
         val state = _uiState.value
@@ -50,7 +54,7 @@ class LoginViewModel @Inject constructor(
             authRepository.signInWithGoogle(idToken)
                 .onSuccess { result ->
                     googleProfileMerger.merge(result)
-                    _uiState.update { it.copy(isLoading = false, success = true) }
+                    _uiState.update { it.copy(isLoading = false, navigateTo = AppRoute.ONBOARDING) }
                 }
                 .onFailure { e -> _uiState.update { it.copy(isLoading = false, error = friendlyError(e)) } }
         }
@@ -62,7 +66,7 @@ class LoginViewModel @Inject constructor(
         _uiState.update { it.copy(isLoading = true, error = null) }
         viewModelScope.launch {
             action()
-                .onSuccess { _uiState.update { it.copy(isLoading = false, success = true) } }
+                .onSuccess { _uiState.update { it.copy(isLoading = false, navigateTo = AppRoute.ONBOARDING) } }
                 .onFailure { e -> _uiState.update { it.copy(isLoading = false, error = friendlyError(e)) } }
         }
     }

app/src/main/java/app/closer/ui/auth/SignUpScreen.kt

@@ -79,11 +79,8 @@ fun SignUpScreen(
     val context = LocalContext.current
     val scope = rememberCoroutineScope()
 
-    LaunchedEffect(state.success) {
+    LaunchedEffect(state.navigateTo) {
-        if (state.success) onNavigate(AppRoute.CREATE_PROFILE)
+        state.navigateTo?.let { onNavigate(it); viewModel.onNavigated() }
-    }
-    LaunchedEffect(state.googleSuccess) {
-        if (state.googleSuccess) onNavigate(AppRoute.ONBOARDING)
     }
     LaunchedEffect(state.error) {
         state.error?.let { snackbar.showSnackbar(it); viewModel.dismissError() }

app/src/main/java/app/closer/ui/auth/SignUpViewModel.kt

@@ -5,6 +5,7 @@ import androidx.lifecycle.viewModelScope
 import app.closer.domain.AgeGate
 import app.closer.domain.SignupHandoff
 import app.closer.ui.brand.CloserCopy
+import app.closer.core.navigation.AppRoute
 import app.closer.domain.repository.AuthRepository
 import app.closer.domain.usecase.GoogleProfileMerger
 import dagger.hilt.android.lifecycle.HiltViewModel
@@ -24,10 +25,10 @@ data class SignUpUiState(
     val isPasswordVisible: Boolean = false,
     val isLoading: Boolean = false,
     val error: String? = null,
-    val success: Boolean = false,
+    // One nullable nav target for both paths (majority navigateTo+onNavigated idiom; self-clearing,
-    // Google sign-up: profile already comes from Google, so route through ONBOARDING
+    // loop-proof): email success → CREATE_PROFILE; google success → ONBOARDING (which decides
-    // (which decides HOME vs CREATE_PROFILE) rather than the email CREATE_PROFILE step.
+    // HOME vs CREATE_PROFILE, since Google already supplies the profile).
-    val googleSuccess: Boolean = false
+    val navigateTo: String? = null
 )
 
 @HiltViewModel
@@ -46,6 +47,7 @@ class SignUpViewModel @Inject constructor(
     fun updateBirthDate(millis: Long) = _uiState.update { it.copy(birthDate = millis, error = null) }
     fun togglePasswordVisibility() = _uiState.update { it.copy(isPasswordVisible = !it.isPasswordVisible) }
     fun dismissError() = _uiState.update { it.copy(error = null) }
+    fun onNavigated() = _uiState.update { it.copy(navigateTo = null) }
 
     fun signUp() {
         val state = _uiState.value
@@ -73,7 +75,7 @@ class SignUpViewModel @Inject constructor(
                     authRepository.currentUserId?.let { uid ->
                         signupHandoff.setPendingBirthDate(uid, dob)
                     }
-                    _uiState.update { it.copy(isLoading = false, success = true) }
+                    _uiState.update { it.copy(isLoading = false, navigateTo = AppRoute.CREATE_PROFILE) }
                 }
                 .onFailure { e ->
                     val msg = friendlyError(e)
@@ -88,7 +90,7 @@ class SignUpViewModel @Inject constructor(
             authRepository.signInWithGoogle(idToken)
                 .onSuccess { result ->
                     googleProfileMerger.merge(result)
-                    _uiState.update { it.copy(isLoading = false, googleSuccess = true) }
+                    _uiState.update { it.copy(isLoading = false, navigateTo = AppRoute.ONBOARDING) }
                 }
                 .onFailure { e -> _uiState.update { it.copy(isLoading = false, error = friendlyError(e)) } }
         }

app/src/main/java/app/closer/ui/onboarding/CreateProfileScreen.kt

@@ -91,8 +91,8 @@ fun CreateProfileScreen(
     val focusManager = LocalFocusManager.current
     val context = LocalContext.current
 
-    LaunchedEffect(state.success) {
+    LaunchedEffect(state.navigateTo) {
-        if (state.success) onNavigate(AppRoute.PAIR_PROMPT)
+        state.navigateTo?.let { onNavigate(it); viewModel.onNavigated() }
     }
     LaunchedEffect(state.error) {
         state.error?.let { snackbar.showSnackbar(it); viewModel.dismissError() }

app/src/main/java/app/closer/ui/onboarding/CreateProfileViewModel.kt

@@ -2,6 +2,7 @@ package app.closer.ui.onboarding
 
 import android.net.Uri
 import androidx.lifecycle.ViewModel
+import app.closer.core.navigation.AppRoute
 import androidx.lifecycle.viewModelScope
 import app.closer.data.remote.FirebaseStorageDataSource
 import app.closer.domain.AgeGate
@@ -38,7 +39,8 @@ data class CreateProfileUiState(
     val birthDateError: String? = null,
     val isLoading: Boolean = false,
     val error: String? = null,
-    val success: Boolean = false,
+    // Majority navigateTo+onNavigated idiom (self-clearing, loop-proof): set to PAIR_PROMPT on save.
+    val navigateTo: String? = null,
     val nameError: String? = null,
     val sexError: String? = null
 )
@@ -191,7 +193,7 @@ class CreateProfileViewModel @Inject constructor(
             }.onSuccess {
                 // DOB is now on the doc — drop the in-memory handoff so a later sign-up can't inherit it.
                 signupHandoff.clear(uid)
-                _uiState.update { it.copy(isLoading = false, success = true) }
+                _uiState.update { it.copy(isLoading = false, navigateTo = AppRoute.PAIR_PROMPT) }
             }.onFailure { e ->
                 _uiState.update { it.copy(isLoading = false, error = e.message ?: "Couldn't save your profile. Please try again.") }
             }
@@ -199,4 +201,5 @@ class CreateProfileViewModel @Inject constructor(
     }
 
     fun dismissError() = _uiState.update { it.copy(error = null) }
+    fun onNavigated() = _uiState.update { it.copy(navigateTo = null) }
 }