fix(control-plane): build local client before production build

[koriyoshi2041]

Fixes #2561.

Problem:

• The control plane depends on the local TypeScript client via file:../hindsight-clients/typescript.
• A clean checkout can run npm run build in the control plane before the client dist files exist or match current source.

Fix:

• Add a prebuild step for the control plane that builds @vectorize-io/hindsight-client first.

Validation:

• npm run prebuild --workspace=hindsight-control-plane
• npm run build --workspace=hindsight-control-plane

Risk:

• Low. This uses the existing client build script and only changes the control-plane build order.

[koriyoshi2041]

Re-ran the control-plane build path on this branch after syncing with current main:

• npm run prebuild --workspace=hindsight-control-plane
• npm run build --workspace=hindsight-control-plane

Both pass locally. The build also regenerated the local TypeScript client first, then completed the Next production build and standalone packaging.