test: migrate examples to XXXX-category-name layout + split expected streams

Rename all example tests/companions to the XXXX-category-test-name scheme
(per-category 100-blocks: basic 0010, types 0100, ... errors 1000,
diagnostics 1100, ffi 1200, ffi-objc 1300, ffi-jni 1400, vectors 1500,
platform 1600). Companions and dir/C fixtures move in lockstep with their
parent test; #import/#source/#include paths rewritten to match.

Expected output now lives in examples/expected/ (a sibling dir of the
tests) split into three streams per the new convention:
  <name>.exit / <name>.stdout / <name>.stderr  (+ optional <name>.ir)

run_examples.sh rewritten: scans examples/ and issues/ for an
expected/<name>.exit marker, captures stdout and stderr separately (no
more 2>&1), compares each stream + exit + optional IR snapshot.

Behavior validated unchanged: every renamed test reproduces its prior
merged output + exit (diffs limited to file paths/basenames embedded in
diagnostics + traces, which correctly reflect the new names). Suite:
292 passed, 0 failed. 50-smoke.sx split + issue relocation + docs follow
in subsequent commits.

examples/1306-ffi-objc-foreign-class-chained-dispatch.sx

@@ -0,0 +1,41 @@
+// Chained foreign-class method dispatch: `Cls.static().instance(...)`
+// resolves the inner call's return type so the outer dispatch's
+// receiver type is known. Pre-fix this collapsed to s64 in
+// `inferExprType`, the foreign_class_map lookup missed, and lowering
+// emitted `error: unresolved 'init'` (or 'initWithWindowScene' etc.)
+// — see issues/0043 for the chess uikit.sx C4 migration that hit it.
+//
+// Two return-type shapes covered: explicit `*ClassName` (alloc here)
+// and `*Self` (init). Both must propagate through the chain so the
+// next `.method(...)` finds the foreign-class declaration.
+
+#import "modules/std.sx";
+#import "modules/compiler.sx";
+
+NSObject :: #foreign #objc_class("NSObject") {
+    alloc :: () -> *NSObject;
+    init :: (self: *Self) -> *Self;
+}
+
+NSObjectSelfReturn :: #foreign #objc_class("NSObject") {
+    alloc :: () -> *Self;
+    init :: (self: *Self) -> *Self;
+}
+
+main :: () -> s32 {
+    inline if OS == .macos {
+        a := NSObject.alloc().init();
+        if a != null {
+            print("explicit-then-self ok\n");
+        }
+        b := NSObjectSelfReturn.alloc().init();
+        if b != null {
+            print("self-then-self ok\n");
+        }
+    }
+    inline if OS != .macos {
+        print("explicit-then-self ok\n");
+        print("self-then-self ok\n");
+    }
+    0;
+}