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/port_new.ludic

@@ -0,0 +1,11 @@
+# L3: a port is not a record a program makes - it is filled once, by `bind`
+program PortNew {
+  port Clock { now: fn() -> int }
+  function hours() -> int {
+    return 3
+  }
+  entry {
+    let c = new Clock
+    print(0)
+  }
+}

examples/rejected/uses_package.ludic

@@ -0,0 +1,7 @@
+# L3: a package's module counts under `uses` like any other - ludic_inventory is not named
+import "uses_pkg_mech"
+program UsesPackage {
+  entry {
+    print(stock())
+  }
+}

examples/rejected/uses_pkg_mech/index.ludic

@@ -0,0 +1,8 @@
+# uses_pkg_mech/index.ludic - a mechanic that says it uses ludic_base, then reaches into another
+# mechanic package
+module mech uses ludic_base
+import "ludic.base"
+import "ludic.inventory"
+export function stock() -> int {
+  return inv_count(0)
+}

examples/rejected/uses_r3d_mech/index.ludic

@@ -0,0 +1,7 @@
+# uses_r3d_mech/index.ludic - a mechanic that reaches into the renderer, which has no module line
+module mech uses ludic_base
+numbers float
+import "ludic.render3d/fmath.ludic"
+export function circle() -> float {
+  return PI * 2.0
+}

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())
+  }
+}