build(scripts): parallelize the import build and dev lifecycle

[PhearZero]

ℹ Overview

• adds wait-on, concurrently and nodemon
• adds watcher for changes to d2 diagrams for hot reloading
• splits dev to run in parallel
• optimizes init life-cycle
• splits import to run in parallel
• fixes teal language definition

✅ Acceptance:

• Lint passes

[larkiny]

Closing this PR as the majority of the changes are now obsolete — submodules were removed (#398), diagram generation scripts no longer exist, and the import workflow was fully reworked (#401, #413, #431).

The Teal syntax fix in ec.config.mjs (switching from fs.readFileSync to a static JSON import + adding stub language definitions) is still relevant and will be reimplemented in a separate PR.