fix(0130): #library/#framework collection recurses into nested namespaces

extractLibraries/extractFrameworks walked the merged root plus exactly
one namespace_decl level, so a #library reached through two or more
aliased imports never made it to the AOT link line or the JIT dlopen
list. Both walks now recurse over namespace_decl children.

Regression: examples/1617-modules-library-nested-namespace.sx binds
libpcap (not in the compiler's loaded images, so the JIT cannot mask
the miss via RTLD_DEFAULT) behind two aliased imports.

examples/1617-modules-library-nested-namespace/b.sx

@@ -0,0 +1,5 @@
+// Middle module: aliases c.sx, putting its #library one namespace deep.
+#import "modules/std.sx";
+c :: #import "c.sx";
+
+version_via_b :: () -> string { return c.pcap_version(); }