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/HermesControlApp.kt

@@ -8,6 +8,9 @@ class HermesControlApp : Application() {
     override fun onCreate() {
         super.onCreate()
         AuthManager.init(this)
+        // Issue #478: guarantee a "Default" profile is always selected so there is no
+        // separate standalone/default code path anywhere in the app.
+        AuthManager.ensureDefaultProfile()
         NetworkMonitor.init(this)
     }
 }