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/0750-modules-forward-alias-source-aware.sx

@@ -0,0 +1,31 @@
+// Source-aware forward-alias fixpoint (R5 §4, E1.5). A forward identifier alias
+// `A :: B` must resolve its target `B` AS SEEN FROM ITS OWN SOURCE, not via the
+// global `type_alias_map` (which is last-wins across every module).
+//
+// `main` authors a forward alias `A :: B` and its own `B :: u64`. The namespaced
+// import `ns :: #import ".../dep.sx"` ALSO authors a top-level `B :: u8`; being
+// scanned after main's `B`, dep's alias is what the GLOBAL `type_alias_map["B"]`
+// ends up holding (last-wins). A global forward-alias fixpoint therefore bound
+// `A` to dep's `u8` — re-opening 0105 one layer down. The source-aware fixpoint
+// resolves `A`'s target against MAIN's source, binding the local `B :: u64`.
+//
+// Observable: a runtime 300 coerced into an `A`-typed slot round-trips as 300
+// when `A` is `u64` (correct) and truncates to 44 when `A` is wrongly `u8`.
+// The direct reference `b : B` already resolves source-aware via E1's nominal
+// leaf, so it pins the same `u64` for contrast. Regression (stdlib E1.5).
+#import "modules/std.sx";
+
+A :: B;
+B :: u64;
+
+ns :: #import "0750-modules-forward-alias-source-aware/dep.sx";
+
+main :: () -> i32 {
+    n : i64 = 300;
+    a : A = xx n;
+    b : B = xx n;
+    print("forward A (u64=300): {}\n", cast(i64) a);
+    print("direct  B (u64=300): {}\n", cast(i64) b);
+    print("ns.width():          {}\n", ns.width());
+    return 0;
+}