Update logos, add banner, and enhance UI with tests

[HarshPanchal01]

Summary of Changes

This pull request updates the application's branding assets and improves platform-specific icon handling across the codebase. It also refines several UI elements for better dark mode support and makes a minor fix to the Yahoo Finance API usage. The most significant changes are grouped below:

Branding and Icon Updates:

• Replaced old icon and logo assets (icon.svg, logo.png, icon.png) with new platform-specific icons and lockups (e.g., onefinance_icon_win_light.png, onefinance_icon_mac_light.png, and corresponding lockup images). Electron builder configuration and asset references throughout the app have been updated to use these new files. (electron-builder.json, electron/main.ts, src/components/Sidebar.vue, src/views/settings/SettingsView.vue) [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
• Updated UI layouts to better accommodate new branding (e.g., simplified app header and info sections, adjusted image sizing and placement). (src/components/Sidebar.vue, src/views/settings/SettingsView.vue) [1] [2] [3]

Dark Mode and UI Improvements:

• Enhanced dark mode appearance for toggle switches by adding a translucent dark-mode overlay to the primary color when enabled, improving visual clarity. (src/views/investments/components/PriceAlertModal.vue, src/views/recurring/RecurringView.vue, src/views/recurring/components/RecurringModal.vue, src/views/settings/SettingsView.vue) [1] [2] [3] [4] [5] [6] [7] [8]
• Removed the Google Fonts import for Inter and switched to using Tailwind's font-sans utility for font family, simplifying font management. (src/style.css) [1] [2]

API and Data Handling:

• Updated Yahoo Finance API usage: replaced the deprecated historical() method with chart(), handling null-close rows manually and disabling schema validation to better accommodate Yahoo's API changes. (electron/finance.ts) [1] [2]

These changes collectively modernize the app's appearance, improve cross-platform consistency, and address some technical debt in API usage and styling.