Move CI, dev tools, and configs from root-level scattered locations into
a
unified `dev/` directory structure. Update all references across build
scripts, documentation, and editor configurations.

Also consolidate editor config generation into build.rs for automated
synchronization of rust-analyzer settings across VS Code and Zed.

suffix

Add `markdown-compare` and `markdown-compare-all` commands to verify
that translated docs maintain the same structure as the reference.
Compare heading levels, code fences, lists, quotes, and other
structural elements while allowing text differences.

Add a new `test-all` command that runs tests across all crates with
optional per-crate command overrides via `mingling-ci.toml` files.

Extract the duplicate parallel check logic from build-all and
clippy-all tasks into a shared `run_parallel_checks` helper.
Update renderers to set exit code instead of printing failure
counts.