Support for 6 languages. Fix data extraction (conflict with macOS .spotlight files)

Major Features - **Home Screen Dashboard**: A new `HomeScreen` is added as the main landing page after login. It provides an at-a-glance overview of analytics, including: - User/client profile card with editable name and age. - A "Risk of Fall" assessment card that calculates and displays fall risk probability based on heel strike data and age. - Key statistics like total sessions and last session date. - A "Sessions per Week" bar chart to visualize usage over time. - **Multi-Client & Single-User Modes**: - The app now supports both a "Single User Mode" and a "Multi-Client Clinic Mode," selectable via a switch on the home screen. - In multi-client mode, users can select a specific client from a dropdown to filter analytics or add new clients. - Client data (name and age) is now stored and managed in a `clientsLocal` sub-collection in Firestore. - **Risk of Fall Analytics**: - A new `RiskOfFallCalculator` helper implements a logistic regression model to predict fall risk probability from heel strike values and age. - A dedicated `RiskOfFall` screen provides a detailed breakdown of the assessment. - **Client Profile Management**: - A new `EditUserProfile` dialog allows users to update their name and age (in single-user mode) or the active client's age (in multi-client mode). - User and client profiles are now displayed consistently across the app using new `UserProfileCard` and `UserProfileCondensed` widgets. - notification and auto refresh screen when session data has completed cloud processing Refinements & Fixes - **UI/UX**: - The UI for Gait Quality, Gait Fatigue, and History charts has been made responsive to improve usability on smaller screens. - The main "Upload" screen (`dashboard.dart`) now shows platform-specific images and improved instructions for connecting the Heel2Toe device. - The `step_analytics_screen` now defaults to the active client's data when in multi-client mode. - Dialogs for cleaning the SD card and uploading files have been redesigned for better clarity and user experience. - **File & Data Handling**: - Client names in session files are now automatically normalized based on the current user mode to ensure data consistency. - File I/O for iOS has been improved to handle expired security-scoped resource access more gracefully when reading from and writing to the device. - The bottom navigation has been updated, making "Home" the new initial tab. - **Authentication Flow**: - The authentication flow now correctly navigates to the new `HomeScreen` after login or consent. - The sign-out process is more robust, ensuring Firestore listeners are detached before logging out to prevent permission errors.

improved step analytics recommended exercises bug fixes