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/0787-modules-same-name-const-ambiguous.sx

@@ -0,0 +1,14 @@
+// issue 0105 / F2 — same-name VALUE const, two-flat-visible → AMBIGUOUS. `main`
+// flat-imports two modules that each author a same-name `K` and authors none
+// itself. A bare `K` reference can't be disambiguated, so the compiler emits a
+// LOUD diagnostic (consistent with the type ambiguity at 0755 and the function
+// ambiguity at 0724) and poisons the result — never a silent first-/last-wins
+// pick.
+#import "modules/std.sx";
+#import "0787-modules-same-name-const-ambiguous/a.sx";
+#import "0787-modules-same-name-const-ambiguous/b.sx";
+
+main :: () -> i32 {
+    print("K={}\n", K);
+    0
+}