Workspace Toolchain Overhaul

[officialMECH]

This PR makes improvements to the development environment and workspace configurations for better reproducability and onboaring when building the project locally.

Technical Changes

• Mise has been integrated as a polyglot for workspace binaries and compilation tasks, which removes the complexity with fragmented binary installs and sandboxing.
• Migrated from Yarn Berry to pnpm for more secure defaults and hardening for potential supply chain attacks, as well as a content addressable store for caching dependency installs across runs and worktrees.
• All workflows now have streamlined event triggers to prevent duplicate runs, and a new local action was added to ensure dependencies are cached across workflow runs.
• VS Code workspace settings now have looser constraints where they'll be less likely to conflict with user settings.
• All docs and guides related to workspace setup were cleaned up based on these aforementioned changes.