feat: implement unified loading screens across various components

- Introduced a new UnifiedLoadingScreen component for consistent loading indicators in the application.
- Replaced existing loading implementations in LoginPage, AuthCallbackPage, DashboardLayout, and other components with the new unified loading screen.
- Updated translations for loading messages to enhance user experience and clarity.
- Improved loading states in the ElectricProvider and TokenHandler components to utilize the new loading screen, ensuring a cohesive look and feel during loading processes.

surfsense_web/messages/en.json

@@ -2,7 +2,8 @@
 	"common": {
 		"app_name": "SurfSense",
 		"welcome": "Welcome",
-		"loading": "Loading...",
+		"loading": "Loading",
+		"initializing": "Initializing",
 		"save": "Save",
 		"cancel": "Cancel",
 		"delete": "Delete",
@@ -76,9 +77,10 @@
 		"passwords_no_match": "Passwords do not match",
 		"password_mismatch": "Password Mismatch",
 		"passwords_no_match_desc": "The passwords you entered do not match",
-		"creating_account": "Creating your account...",
-		"creating_account_btn": "Creating account...",
-		"redirecting_login": "Redirecting to login page..."
+		"creating_account": "Creating your account",
+		"creating_account_btn": "Creating account",
+		"redirecting_login": "Redirecting to login page",
+		"processing_authentication": "Processing authentication"
 	},
 	"searchSpace": {
 		"create_title": "Create Search Space",
@@ -143,12 +145,15 @@
 		"api_keys": "API Keys",
 		"profile": "Profile",
 		"loading_dashboard": "Loading Dashboard",
-		"checking_auth": "Checking authentication...",
+		"checking_auth": "Checking authentication",
 		"loading_config": "Loading Configuration",
-		"checking_llm_prefs": "Checking your LLM preferences...",
+		"checking_llm_prefs": "Checking your LLM preferences",
+		"setting_up_ai": "Setting up AI",
 		"config_error": "Configuration Error",
 		"failed_load_llm_config": "Failed to load your LLM configuration",
 		"error_loading_chats": "Error loading chats",
+		"loading_chat": "Loading chat",
+		"loading_document": "Loading document",
 		"no_recent_chats": "No recent chats",
 		"error_loading_space": "Error loading search space",
 		"unknown_search_space": "Unknown Search Space",
@@ -165,7 +170,7 @@
 		"create_search_space": "Create Search Space",
 		"add_new_search_space": "Add New Search Space",
 		"loading": "Loading",
-		"fetching_spaces": "Fetching your search spaces...",
+		"fetching_spaces": "Fetching your search spaces",
 		"may_take_moment": "This may take a moment",
 		"error": "Error",
 		"something_wrong": "Something went wrong",