feat: enhanced Project management UI for better experience

[Yashh56]

This pull request focuses on updating the font system and refining navigation related to projects in the application. The main changes include switching the default fonts to IBM Plex, removing the global "Projects" navigation entry, and ensuring project navigation links directly to the associated database. Additionally, there are numerous code style improvements for better readability and maintainability.

Font and Design System Updates:

• Switched the default font family to IBM Plex Sans and IBM Plex Mono in both index.html and src/App.css, replacing Geist fonts. (index.html, src/App.cssR6-R20)
• Updated .font-sans and .font-mono utility classes to use IBM Plex fonts. (src/App.css, src/App.cssR6-R20)
• Improved formatting and consistency of CSS variables and gradients for better readability and maintainability. (src/App.css, [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]

Navigation and Project Handling:

• Removed the global "Projects" navigation entry from both the command palette and the vertical icon bar, streamlining navigation. (src/components/layout/CommandPalette.tsx, [1]; src/components/layout/VerticalIconBar.tsx, [2] [3]
• Updated project navigation so selecting a project in the command palette now navigates directly to its linked database route (e.g., /<databaseId>) instead of a generic /projects page. (src/components/layout/CommandPalette.tsx, src/components/layout/CommandPalette.tsxL421-R421)
• Adjusted logic for determining the current database ID in the command palette to reflect the removal of the /projects route. (src/components/layout/CommandPalette.tsx, src/components/layout/CommandPalette.tsxL192-R192)
• Clarified comments to indicate that the "Projects" group in the command palette navigates to the linked database. (src/components/layout/CommandPalette.tsx, src/components/layout/CommandPalette.tsxL410-R409)

Code and Style Cleanups:

• Reformatted complex CSS properties (e.g., box-shadow, background gradients, transitions) for improved clarity and maintainability. (src/App.css, multiple references)
• Removed redundant or unnecessary CSS selectors related to user-select. (src/App.css, src/App.cssL464-R501)

These changes modernize the UI's typography, clarify navigation, and improve code quality for future maintenance.