chore: install dogfood image tooling via mise.toml (#25282)

This PR replaces the hand-rolled `curl | tar | go install | cargo
install` chains in the dogfood Ubuntu 22.04 and 26.04 Dockerfiles with a
single `mise install` driven by a new repo-root `mise.toml`.

The previous Dockerfiles installed ~25 CLIs across three multi-stage
builds with versions hardcoded inline. Version bumps were scattered
across the Dockerfiles, the root `mise.toml` (added in #24618 but
otherwise unused at runtime), and CI's setup actions; build-time network
failures came from a dozen distinct endpoints; and `mise` itself sat in
the image with no manifest to install from.

The new flow:

- The repo's `mise.toml` is the single source of truth for image tool
versions. The Dockerfiles `COPY` it to `/etc/mise/config.toml` and run a
single `mise install` as the `coder` user.
- Tools are installed into `/opt/mise/data` rather than the default
`/home/coder/.local/share/mise`, so they live in the image (not on the
persistent home volume) and reach every workspace on recreate.
- Build context moves to the repo root so the Dockerfile can `COPY
mise.toml`; an allowlist `.dockerignore` keeps the transferred context
to ~24 kB.
- Optional `--secret id=github_token` plumbing through the Makefile and
`.github/workflows/dogfood.yaml` lifts aqua's GitHub API quota from
60/hr unauthenticated to 1000/hr with `secrets.GITHUB_TOKEN`.
- `MISE_TRUSTED_CONFIG_PATHS=/home/coder:/etc/mise` is set as an ENV so
users who clone the coder repo into their workspace home aren't prompted
to `mise trust`.

Net diff for the two Ubuntu Dockerfiles: -399 / +244 lines (~200 lines
shorter each). The `FROM rust-utils`, `FROM go`, and `FROM proto`
multi-stage builds are gone; so are the NVM/Node block, the bulk
binary-install block (golangci-lint, helm, kubectx, syft, cosign, bun),
the gh `.deb`/lazygit/doctl tarball installs, the gofmt
`update-alternatives` line, and the `yq`→`yq4` rename
(`scripts/lib.sh:267-275` already auto-detects either name).

Both images were built and smoke-tested with Apple's `container` CLI on
macOS — every migrated tool resolves to the expected pinned version
including outside the cloned coder repo (e.g. `gh` from `/home/coder`,
matching the workspace startup script in `dogfood/coder/main.tf`),
`sqlc` runs (proving `CGO_ENABLED=1` was honoured at install), `yq
--version` reports v4 for `scripts/lib.sh`'s detection, and `gofmt`
resolves via the mise shim.

Follow-ups (out of scope here):

- Commit a multi-platform `mise.lock` so `gh = "latest"` and the other
floating versions resolve deterministically across rebuilds and dev
machines.
- Migrate CI's `setup-go` / `setup-node` actions to consume `mise.toml`
so image and CI versions stop being able to drift.

---------

Signed-off-by: Thomas Kosiewski <tk@coder.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Makefile

@@ -745,7 +745,7 @@ lint/ts: site/node_modules/.installed
 .PHONY: lint/ts
 
 lint/go:
-	linter_ver=$$(grep -oE 'GOLANGCI_LINT_VERSION=\S+' dogfood/coder/ubuntu-26.04/Dockerfile | cut -d '=' -f 2)
+	linter_ver=$$(grep -Eo '^golangci-lint = "[^"]+"' mise.toml | sed -E 's/.*"([^"]+)"/\1/')
 	go run github.com/golangci/golangci-lint/cmd/golangci-lint@v$$linter_ver run
 	go tool github.com/coder/paralleltestctx/cmd/paralleltestctx -custom-funcs="testutil.Context,chatdTestContext" ./...
 	go run ./scripts/intxcheck ./...