fix(auth): remove auto-signout on 401 in AuthInterceptor

The AuthInterceptor was calling signOut() on any 401 error, which caused
the theme toggle to trigger logout when the preferences API returned 401.
Now 401 errors propagate to calling code for graceful handling.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.1.16] - 2026-01-05
+
+### Fixed
+- Theme toggle causing logout due to AuthInterceptor auto-signout on 401
+  - Removed aggressive `signOut()` call in `AuthInterceptor.onError`
+  - 401 errors now propagate to calling code for graceful handling
+  - Preferences API 401 no longer triggers full logout redirect
+
 ## [1.1.15] - 2026-01-05
 
 ### Fixed

lib/core/api/api_interceptors.dart

@@ -38,16 +38,9 @@ class AuthInterceptor extends Interceptor {
 
   @override
   void onError(DioException err, ErrorInterceptorHandler handler) {
-    // Skip auth error handling for LAN development
+    // Don't auto-signout on 401 - let calling code handle auth errors gracefully.
-    if (!AppConfig.requiresAuth) {
+    // Auto-signout was causing issues (e.g., theme toggle triggering logout when
-      handler.next(err);
+    // preferences API returned 401).
-      return;
-    }
-
-    if (err.response?.statusCode == 401) {
-      // Token expired - trigger re-authentication
-      _ref.read(authProvider.notifier).signOut();
-    }
     handler.next(err);
   }
 }

pubspec.yaml

@@ -16,7 +16,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 1.1.15+1
+version: 1.1.16+1
 
 environment:
   sdk: ^3.10.4