fix(ci): pass monorepo lockfile and install paths to publish workflow

The reusable publish-npm-package workflow now supports lockfile-path and
install-path inputs. Pass these so it finds pnpm-lock.yaml at the repo
root and runs pnpm install from the root, matching the monorepo layout.

https://claude.ai/code/session_01CnQyyfrELDqC87N3ts334h

Author: claude

.github/workflows/publish-datum-ui.yml

@@ -23,6 +23,8 @@ jobs:
     with:
       package-name: "@datum-cloud/datum-ui"
       package-path: packages/datum-ui
+      lockfile-path: pnpm-lock.yaml
+      install-path: "."
 
   # Alpha publish on PR with 'alpha' label
   alpha: