ios + ir cleanup

- ios: --target ios/ios-sim shorthands, iOS SDK auto-discovery,
  #framework directive + BuildOptions.add_framework hook,
  .app bundle + Info.plist + codesign (ad-hoc and real),
  --codesign-identity/--provisioning-profile/--entitlements flags,
  modules/std/{objc,uikit}.sx, dynamic class registration,
  typed objc_msgSend cast pattern, UIApplicationMain handoff,
  UIWindow scene attach. Runs on iPhone hardware.
- ir: silent .s64 defaults → loud diagnostics,
  resolveReturnType infers from body, sub-byte int sizes match LLVM,
  tuple type interning includes names, compile errors exit 1
- issue-NNNN convention: resolved bugs rename to focused features
- 50 regression tests passing

examples/63-uikit-app.sx

@@ -0,0 +1,41 @@
+// Minimal iOS app entry point — pure sx, no .m files.
+//
+// 1. Register a class `SxAppDelegate : UIResponder <UIApplicationDelegate>`
+//    dynamically, with one method:
+//       application:didFinishLaunchingWithOptions: returns YES (BOOL 1).
+// 2. Call UIApplicationMain(0, null, null, @"SxAppDelegate") to hand off to
+//    UIKit's run loop. This blocks until the app exits.
+//
+// After install + launch, the simulator shows the default black screen
+// (UIWindow not created — that's 5.8) and the AppDelegate callback fires
+// once at startup. The process stays alive because UIApplicationMain
+// drives the iOS run loop.
+
+#import "modules/std.sx";
+#import "modules/std/uikit.sx";
+
+// IMP for application:didFinishLaunchingWithOptions:
+//   Obj-C: -(BOOL)application:(UIApplication *)app didFinishLaunchingWithOptions:(NSDictionary *)opts
+//   Type encoding: "c@:@@"  -- BOOL (signed char), self, _cmd, id, id
+did_finish_launching :: (self: *void, _cmd: *void, app: *void, opts: *void) -> u8 callconv(.c) {
+    NSLog(ns_string("[sx] application:didFinishLaunchingWithOptions: called\n".ptr));
+    return 1; // YES
+}
+
+main :: () -> s32 {
+    // SxAppDelegate : UIResponder. We deliberately don't try
+    // `class_addProtocol(UIApplicationDelegate)` — the linker dead-strips the
+    // protocol metadata from UIKit when nothing references it at compile
+    // time, and the C runtime can't look it up by name. UIApplicationMain
+    // duck-types on the method name, so this works without formal conformance.
+    UIResponder := objc_getClass("UIResponder".ptr);
+    SxAppDelegate := objc_allocateClassPair(UIResponder, "SxAppDelegate".ptr, 0);
+
+    sel := sel_registerName("application:didFinishLaunchingWithOptions:".ptr);
+    class_addMethod(SxAppDelegate, sel, xx did_finish_launching, "c@:@@".ptr);
+
+    objc_registerClassPair(SxAppDelegate);
+
+    // Hand off to the iOS run loop. Never returns under normal operation.
+    return UIApplicationMain(0, xx 0, xx 0, ns_string("SxAppDelegate".ptr));
+}