* fix(ts-plugin): derive routePath from proto package

The TS client generator's routePrefix stripped the `module=` plugin
parameter from the Go import path. Downstream consumers that don't
set `module=` in buf.gen.ts.yaml (e.g. protosource-auth) got the full
Go import path baked into routePath, producing URLs like
`${baseURL}/github.com/.../gen/auth/user/v1/...` that 404 against the
server's `auth/user/v1` routes.

Derive routePath from the proto package declaration (dots → slashes)
instead, removing the dependency on plugin parameters and matching
what the Go-generated server registers.

* fix(go-plugin): derive routePath from proto package

Mirror the TS-plugin change so the Go plugin's routePrefix also derives
from the proto package declaration (dots → slashes) rather than the
Go import path stripped by `module=`. The two plugins now share
identical routePrefix semantics, and the resulting routes no longer
depend on plugin parameters or the proto's go_package option.

Regenerating in-repo example protos produces byte-identical output,
confirming this is a no-op for consumers that today configure
`module=github.com/funinthecloud/protosource`.