Local Library Mods and Specification

Added documentation for using local library mods (forks/overrides) across different ecosystems and drafted specifications for a new Mod Management feature in Dev-Centr.

Changes

Created Local Library Mods guide explaining techniques for DUB, PNPM, Python, and Go.
Drafted Local Mod Management Feature specification.
Updated navigation menus for both the main documentation and the specifications module.

Local Mod Management Specs

The new specification outlines a UI-based approach to managing local repository overrides: * Global Mod List: View all registered overrides across various package managers. * Link/Unlink Actions: Perform operations like dub add-local directly from the dashboard. * Project Badges: Appending [MOD] to project names in the repository browser when an override is active. * Dependency Health: Visualizing which dependencies are local vs. registry-originated.