fix(ci): install @changesets/cli as workspace devDep (#11)

* fix(ci): install @changesets/cli as workspace devDep

The release workflow's `changesets/action@v1` step resolves
`@changesets/cli` from the workspace's node_modules before doing
anything, so a global install via `npm install -g` lets the binary
land on PATH but doesn't satisfy the action's preflight resolve.

Symptom: every merge that *adds* a changeset (vs the follow-up
Version Packages PR, which has no pending changesets and skips the
action's open-version-PR branch) fails the Release job with:

    Error: Have you forgotten to install `@changesets/cli` in
    "/home/runner/work/managed-auth-react/managed-auth-react"?

Fix: add `@changesets/cli` to the root devDependencies so it
resolves from the workspace. Bun does create `node_modules/.bin/changeset`
when it's a workspace dep, so the earlier "bun skips the .bin shim"
workaround is no longer needed and the global-install step is dropped.

* fix(ci): use bunx for changeset publish

The publish input to changesets/action is passed to
@actions/exec.getExecOutput, which does a PATH-based lookup — it does
not search the workspace's node_modules/.bin. With the global install
gone, `changeset publish` would no longer resolve. `bunx` explicitly
resolves to the workspace devDep (verified: returns 2.31.0).

Author: masnwilliams

.github/workflows/release.yaml

@@ -64,14 +64,6 @@ jobs:
       - name: Install dependencies
         run: bun install --frozen-lockfile
 
-      # `bun install` skips the standard node_modules/.bin/changeset shim
-      # that npm/pnpm/yarn create, so neither npx nor PATH-based lookups
-      # find the binary. Installing @changesets/cli globally via npm gives
-      # us a clean `changeset` on PATH for the action below. We keep using
-      # bun for the workspace install so the project lockfile stays in use.
-      - name: Install changesets CLI (global, for binary on PATH)
-        run: npm install -g @changesets/cli
-
       - name: Build package
         run: bun run --filter '@onkernel/managed-auth-react' build
 
@@ -83,7 +75,7 @@ jobs:
       - name: Create release PR or publish
         uses: changesets/action@v1
         with:
-          publish: changeset publish
+          publish: bunx changeset publish
           title: "chore: version packages"
           commit: "chore: version packages"
         env: