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/0788-modules-same-name-const-expr-chain-dim/a.sx

@@ -0,0 +1,9 @@
+// Module A authors its OWN chain: `M :: 1`, `K :: M + 1` (= 2). Both the value
+// read and the array dimension must resolve `K` through A's `M`.
+M :: 1;
+K :: M + 1;
+a_val :: () -> i64 { return K; }
+a_len :: () -> i64 {
+    arr : [K]u8 = ---;
+    return arr.len;
+}

examples/modules/0788-modules-same-name-const-expr-chain-dim/b.sx

@@ -0,0 +1,10 @@
+// Module B authors a DIFFERENT same-name chain: `M :: 10`, `K :: M + 1` (= 11).
+// A shadow of A's `M`/`K`. Each `K`'s RHS leaf resolves to its own source's `M`,
+// so the dimension fold gives B's length 11 — never A's via the global map.
+M :: 10;
+K :: M + 1;
+b_val :: () -> i64 { return K; }
+b_len :: () -> i64 {
+    arr : [K]u8 = ---;
+    return arr.len;
+}