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.sx

@@ -0,0 +1,10 @@
+// Regression (issue 0130): a #library declared in a module reached through
+// TWO aliased imports must still be linked (AOT) / dlopened (JIT).
+#import "modules/std.sx";
+b :: #import "1617-modules-library-nested-namespace/b.sx";
+
+main :: () -> i32 {
+    v := b.version_via_b();
+    print("pcap version non-empty: {}\n", v.len > 0);
+    return 0;
+}

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(); }

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

@@ -0,0 +1,11 @@
+// Innermost module: owns the #library and its foreign fn.
+#import "modules/std.sx";
+
+pcaplib :: #library "pcap";
+pcap_lib_version :: () -> ?cstring #foreign pcaplib "pcap_lib_version";
+
+pcap_version :: () -> string {
+    p := pcap_lib_version();
+    if p == null { return ""; }
+    return from_cstring(p!);
+}

examples/expected/1617-modules-library-nested-namespace.exit

@@ -0,0 +1 @@
+0

examples/expected/1617-modules-library-nested-namespace.stderr

@@ -0,0 +1 @@
+

examples/expected/1617-modules-library-nested-namespace.stdout

@@ -0,0 +1 @@
+pcap version non-empty: true