feat(lang): packages count under uses; a port of defaults may go unbound

A module that says uses must name every package module it reaches; a
package with no module line is named for its directory (ludic_render3d)
for this rule, so a mechanic reaching into the renderer is caught. Only
the engine's runtime needs no naming. 'module x uses' with nothing after
it reaches no other module. A port whose every member has a default
answers with its defaults when unbound, and 'new' of a port says to bind
it. ludic-dev test runs 'ludic test packages'. Reseed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/rejected/uses_render3d.ludic

@@ -0,0 +1,8 @@
+# L3: a package with no module line is still named under `uses` - ludic_render3d is not
+import "uses_r3d_mech"
+program UsesRender3d {
+  numbers float
+  entry {
+    print(circle())
+  }
+}