[Feature] Improve local development setup documentation and workspace resolution #1061

Context

When forking and developing Squad locally, there are issues with:

1. CLI picking up the published npm SDK version instead of the local workspace build
2. Documentation referencing non-existent build scripts
3. Unclear instructions for linking the local build globally

Proposal

This PR (#1059) addresses the documentation and workspace dependency issues:

1. README.md: Added "Local Development Installation" section with npm run dev:link instructions for linking the local build globally

2. docs/src/content/docs/guide/contributing.md: Updated linking instructions to use npm run dev:link and npm run dev:unlink instead of manual npm link commands, and removed references to non-existent npm run build:cli script

Changes

See PR: https://github.com/bradygaster/squad/pull/1059