ci: build root and link @rdcp/server before building otel-plugin

[mojoatomic]

Fix failing main CI:

• Build root package before building otel-plugin (generates dist types)
• Link @rdcp/server into otel-plugin node_modules (no-save) so TS resolves @rdcp/server imports during plugin build

This addresses: TS2307 Cannot find module "@rdcp/server" in otel-plugin build.