test: group examples into per-category folders

Move examples/*.sx and their expected/ snapshots into per-category
subfolders (examples/<category>/...). Folder = leading filename token,
with ffi-objc/ffi-jni kept whole; filenames are unchanged. The corpus
runner and LSP sweep now discover each category's expected/ dir, while
issues/ stays flat. Example 1058's repo-root-relative companion import
is made file-relative. Path strings embedded in 164 snapshots were
regenerated (path-only changes). Test-layout docs in CLAUDE.md updated.

examples/modules/0752-modules-same-name-struct-distinct-fields.sx

@@ -0,0 +1,14 @@
+// issue 0105 case 1 — same-name struct, DIFFERENT fields. Two flat-imported
+// modules each declare a top-level `Box` with a different field set. Each
+// module's function builds and returns ITS OWN `Box`; `main` (which authors no
+// `Box`) prints both. Each value resolves against its declaring module's type,
+// so the formatter shows A's `{x}` and B's `{p, q}` — proving the two `Box`
+// types are distinct nominal identities, not a single last-wins collapse.
+#import "modules/std.sx";
+#import "0752-modules-same-name-struct-distinct-fields/a.sx";
+#import "0752-modules-same-name-struct-distinct-fields/b.sx";
+
+main :: () -> i32 {
+    print("a={} b={}\n", a_box(), b_box());
+    0
+}