fix(FR-2719): build docs-toolkit before PDF run so docs-toolkit CLI is on PATH

backend.ai-docs-toolkit ships its CLI as a package bin pointing at
dist/cli.js. On a fresh `pnpm install`, that file does not exist yet
(tsc has not run), so pnpm silently fails to create the
.bin/docs-toolkit symlink and emits a WARN. The downstream
`pnpm run pdf:all` (which calls `docs-toolkit pdf --lang all`) then
fails with `spawn ENOENT` because the bin is not on PATH.

The fix is a one-time toolkit build + re-install after the initial
install: tsc populates dist/cli.js, then the second install picks up
the now-existing bin and creates the symlink. The original
`pnpm run pdf:all` script's own `build:toolkit` step still rebuilds
the toolkit, but it cannot fix the missing symlink on its own.

Caught by a workflow_dispatch dry run before merging.

Author: yomybaby

.github/workflows/package.yml

@@ -246,6 +246,17 @@ jobs:
       - name: Install Dependencies
         run: pnpm install --no-frozen-lockfile
 
+      # backend.ai-docs-toolkit ships its `docs-toolkit` CLI as the package
+      # bin, but it lives at dist/cli.js which only exists after `tsc` runs.
+      # On a fresh `pnpm install` the dist directory is empty, so pnpm
+      # cannot create the .bin/docs-toolkit symlink and later `pdf:all`
+      # fails with `spawn ENOENT`. Building the toolkit and re-running
+      # install populates dist/ and lets pnpm wire the bin link.
+      - name: Build docs-toolkit and link CLI
+        run: |
+          pnpm --filter backend.ai-docs-toolkit run build
+          pnpm install --no-frozen-lockfile
+
       # Cache the Playwright browser binaries (~150 MB Chromium download).
       # The lockfile hash keys the cache so a Playwright version bump
       # naturally invalidates the cache without manual intervention.