Add project documentation and initial analysis reports

docs/architecture-frontend.md

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+# Frontend Architecture
+
+## Overview
+
+The PriceFlow frontend is a Single Page Application (SPA) built with React 18 and Vite. It provides the user interface for tracking products, viewing history, and configuring settings.
+
+## Technology Stack
+
+- **Core**: React 18
+- **Build Tool**: Vite
+- **Styling**: Tailwind CSS
+- **Components**: Radix UI (headless), Lucide React (icons)
+- **Routing**: React Router DOM
+- **Internationalization**: i18next
+
+## Key Directories
+
+- `src/components/`: Reusable UI components.
+- `src/pages/`: Page-level components mapped to routes.
+- `src/api/` (implied): API integration logic.
+- `src/lib/`: Utilities and helper functions.
+
+## State Management
+
+State is likely managed via React's built-in `useState`/`useContext` hooks, with `axios` handling async data fetching.
+
+## Design System
+
+The UI utilizes Tailwind CSS for utility-first styling and Radix UI primitives for accessible component logic (Dialogs, Tooltips, etc.).