fix(build): delegate build-server and build-sdk to scripts/build.py

The `build-server` and `build-sdk` Make targets ran a raw `uv build`
in the package directory. Both packages declare `agent_control_models`,
`agent_control_engine`, and `agent_control_telemetry` as vendored
packages in their hatch wheel config. Without the pre-build copy that
`scripts/build.py` performs, hatch silently produces a wheel whose
declared package directories are empty on disk:

    $ unzip -l dist/agent_control_server-*.whl | grep telemetry/
    (no match)

The resulting wheel installs cleanly via pip but crashes at startup
because the bundled imports are missing:

    agent-control-migrate: No module named 'agent_control_telemetry'

Delegate `build-models`, `build-server`, and `build-sdk` to the
canonical `scripts/build.py` entry points so that `make build-server`
and `make build-sdk` produce the same wheels as the publish pipeline
runs in CI. Verified: rebuilt wheels now contain
`agent_control_models`, `agent_control_engine`, and
`agent_control_telemetry` under their respective package directories.

`build-models` had no vendored packages, so the previous raw-`uv build`
worked, but routing it through the script keeps the build-target
shape uniform across the three publishable packages.

Author: abhinav-galileo

Makefile

@@ -154,13 +154,14 @@ telemetry-typecheck:
 build: build-models build-server build-sdk engine-build telemetry-build evaluators-build contrib-build
 
 build-models:
-	cd $(MODELS_DIR) && uv build
+	uv run python scripts/build.py models
 
+# scripts/build.py copies vendored workspace packages before building wheels.
 build-server:
-	cd $(SERVER_DIR) && uv build
+	uv run python scripts/build.py server
 
 build-sdk:
-	cd $(SDK_DIR) && uv build
+	uv run python scripts/build.py sdk
 
 telemetry-build:
 	cd $(TELEMETRY_DIR) && uv build