## Summary
This PR starts Phase 1 of PLEN-1368 by adding `mise.toml` as the
repo-owned source for the primary toolchain versions:
- Node `20.20.2`
- Bun `1.3.10`
- Deno `2.6.7`
- Python `3.12`
- uv `0.8.19`
It also keeps pnpm corepack-driven through
`package.json#packageManager`, adds `devEngines` for Node/pnpm
visibility, documents the new `mise install && corepack enable && pnpm
install` bootstrap path, ignores `.mise.local.toml`, and fixes stale
release-doc prerequisites.
## Why
The repo already has real toolchain drift, not just duplicated version
strings. The internal release docs had stale Node/Bun/pnpm versions,
Deno is repeated across workflows, Dockerfiles, docs, and e2e helpers,
and Python local setup still has a separate `3.11` venv path while the
repo pins `3.12`.
A composite-action cleanup would improve CI, but it would not solve
local development. `mise.toml` gives us one file that declares the
versions and lets contributors install or switch them with one command.
That is the main value proposition here: make the repo declare its own
toolchain, then let CI consume the same declaration in the next phase.
## Rollout
This is deliberately additive. It does not remove `.nvmrc`,
`.bun-version`, `.python-version`, or `.dvmrc`, and it does not change
CI behavior yet. Contributors who do not use mise can keep working as
before; contributors who do use mise get managed Node/Bun/Deno/Python/uv
immediately.
Phase 2 can migrate the existing composite actions to
`jdx/mise-action@v4`. Phase 3 can remove the legacy version files and
add the lockfile once the transition is complete.
## Out of Scope
- Migrating CI to `jdx/mise-action@v4`
- Removing legacy version files
- Adding `mise.lock`
- Updating nested TS package/example `packageManager` fields that still
say `pnpm@10.28.0`; that is pre-existing metadata drift and should be
handled separately to avoid broadening Phase 1
## Verification
- `git diff --check origin/next...HEAD`
- `mise install && mise current`
- `pnpm --version` -> `10.28.2`
- `pnpm dlx prettier@3.8.1 --check package.json`
Refs: PLEN-1368
Alberto Schiabel