chore: use standard package structure

[marioparaschiv]

This pull request restructures the repository to move the main client bundle into a dedicated packages/bundle directory, updates the build tooling (switching from pnpm to bun), and modernizes project dependencies and scripts. It also removes the i18n submodule in favor of a local package, updates documentation to reflect these changes, and standardizes import paths throughout the codebase for better maintainability.

Repository structure and build tooling changes:

• Moved the main client code and build configuration into packages/bundle, with a new package.json specifying updated dependencies, scripts, and linking to local packages for i18n and types.
• Replaced the previous root-level build setup (including package.json and nodemon.json) with a new setup using bun for dependency management and scripts, and updated the build/dev scripts accordingly. [1] [2]
• Removed the i18n submodule and now reference it as a local package, simplifying dependency management. (.gitmodules [1] i18n [2] [3]

Codebase modernization and import path standardization:

• Refactored all internal import paths in the bundle to use the ~/ alias and updated references to types and i18n to use the new @unbound-app package names. [1] [2] [3] [4] [5] [6] [7] [8]
• Updated rollup.config.mjs (now in packages/bundle) to use the new structure, improved error handling, and changed the injected version variable to $VERSION$ for clarity. [1] [2] [3]
• Adjusted dynamic imports and module references to align with the new directory structure and import conventions. [1] [2] [3]

Documentation updates:

• Updated README.md and CONTRIBUTING.md to reflect the new repository location, build instructions (using bun instead of pnpm), and removed references to the old submodule setup. [1] [2] [3] [4]

Other improvements:

• Minor fixes such as correcting typos in documentation and improving error messages in the build configuration. [1] [2]

References: [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23]