fix(#478): rework default login to use unified ConnectionProfile model (#482)

* fix(#478): rework default login to use unified ConnectionProfile model

- AuthManager: drop legacy auth_token path; getToken/setToken now delegate
  to the selected profile (profile token only, no global fallback)
- setHost/setPort always write the selected profile (no top-level host/port branch)
- Add DEFAULT_PROFILE_ID + ensureDefaultProfile()/ensureDefaultSelected() so the
  selected profile is never null; ensureDefaultSelected() only falls back when
  nothing is selected (never clobbers an existing choice); ensureDefaultProfile()
  only injects a Default profile on fresh install, never into an existing list
- One-time migration folds legacy standalone auth_token into the Default profile,
  batched into a single SharedPreferences transaction (guarded by legacy_default_migrated)
- ConnectViewModel.connect() persists via setToken/setHost/setPort (delegate to
  the selected profile) — keeps the existing persistence contract
- Connect/Settings: remove the '(none)'/standalone profile option; deleteProfile
  falls back to Default profile instead of null selection
- Update AuthManagerTest/ConnectViewModelTest to the unified model; fix test
  stub ordering + migration re-init; remove dead connect_profile_none / settings_profile_none strings

Closes #478

* fix: stub AuthManager.ensureDefaultSelected() in E2eIntegrationTest

The #478 ConnectViewModel.connect() success branch now calls
AuthManager.ensureDefaultSelected() on the non-saveProfile path.
E2eIntegrationTest.setUp() mocks AuthManager as a non-relaxed mockkObject
but never stubs that method, so the unstubbed call throws MockKException inside
viewModelScope.launch, leaving connectionSuccess unset and failing 3 tests:
- testFullUserSessionFlow
- testConnectViewModel_onPairingString_base64Format
- testConnectViewModel_onPairingString_urlFormat

Add the missing stub. Verified locally: full suite 322/322 passing.

---------

Co-authored-by: ronia <ronia@m57>

app/src/main/java/com/m57/hermescontrol/ui/settings/SettingsScreen.kt

@@ -359,13 +359,6 @@ private fun ConnectionSection(
                     onDismissRequest = { profilesExpanded = false },
                     modifier = Modifier.fillMaxWidth(0.85f),
                 ) {
-                    DropdownMenuItem(
-                        text = { Text(stringResource(R.string.settings_profile_none)) },
-                        onClick = {
-                            viewModel.selectProfile(null)
-                            profilesExpanded = false
-                        },
-                    )
                     state.profiles.forEach { profile ->
                         DropdownMenuItem(
                             text = { Text(profile.name) },

app/src/main/java/com/m57/hermescontrol/ui/settings/SettingsViewModel.kt

@@ -127,8 +127,13 @@ class SettingsViewModel(
         val updatedProfiles = AuthManager.getConnectionProfiles().filter { it.id != profileId }
         AuthManager.saveConnectionProfiles(updatedProfiles)
         AuthManager.setProfileToken(profileId, null)
+        // Never leave selection null (issue #478): if the deleted profile was selected,
+        // fall back to the default profile instead of clearing selection.
         if (AuthManager.getSelectedProfileId() == profileId) {
-            AuthManager.setSelectedProfileId(null)
+            if (updatedProfiles.none { it.id == AuthManager.DEFAULT_PROFILE_ID }) {
+                AuthManager.ensureDefaultProfile()
+            }
+            AuthManager.setSelectedProfileId(AuthManager.DEFAULT_PROFILE_ID)
         }
         viewModelScope.launch(ioDispatcher) { loadSettings() }
         ApiClient.rebuild()