refactor(ffi-linkage): Phase 7.2 — migrate 13xx ffi-objc examples #foreign→extern

18 obj-c examples migrated (1308/1311-1317/1319/1320/1321/1341-1347): import
runtime classes '#foreign #objc_class("X") {' → '#objc_class("X") extern {'
(prefix→postfix) + fn/comment '#foreign'→'extern'. No 13xx snapshot asserts on
'foreign' text → all behavior-preserving; empty snapshot diff, corpus-validated.

Per the keep-list policy: KEPT identity-#foreign tests 1306/1318 (filename
ffi-*-foreign*); LEFT comment-only #foreign in the extern/export test files
1332/1348/1349 (no decls). Bare defined #objc_class examples (no #foreign) untouched
— not a purge target. Suite green (647 corpus / 444 unit, 0 failed).

examples/1308-ffi-objc-type-aliases.sx

@@ -16,7 +16,7 @@
 #import "modules/ffi/objc.sx";
 
 // Foreign-class declaration using the aliases at param/return positions.
-NSObjectAlias :: #foreign #objc_class("NSObject") {
+NSObjectAlias :: #objc_class("NSObject") extern {
     alloc :: () -> *Self;
     init  :: (self: *Self) -> *Self;
     isKindOfClass :: (self: *Self, cls: Class) -> BOOL;

examples/1311-ffi-objc-class-ivar-registration.sx

@@ -20,7 +20,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-class_getInstanceVariable :: (cls: *void, name: [*]u8) -> *void #foreign objc;
+class_getInstanceVariable :: (cls: *void, name: [*]u8) -> *void extern objc;
 
 SxFoo :: #objc_class("SxFoo") {
     counter: i32;

examples/1312-ffi-objc-class-method-dispatch.sx

@@ -15,7 +15,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-class_getMethodImplementation :: (cls: *void, sel: *void) -> *void #foreign objc;
+class_getMethodImplementation :: (cls: *void, sel: *void) -> *void extern objc;
 
 SxFoo :: #objc_class("SxFoo") {
     counter: i32;

examples/1313-ffi-objc-class-alloc-roundtrip.sx

@@ -18,7 +18,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-class_getInstanceVariable :: (cls: *void, name: [*]u8) -> *void #foreign objc;
+class_getInstanceVariable :: (cls: *void, name: [*]u8) -> *void extern objc;
 
 SxFoo :: #objc_class("SxFoo") {
     counter: i32;

examples/1314-ffi-objc-class-dealloc-roundtrip.sx

@@ -16,8 +16,8 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-class_getInstanceVariable :: (cls: *void, name: [*]u8) -> *void #foreign objc;
-class_getMethodImplementation :: (cls: *void, sel: *void) -> *void #foreign objc;
+class_getInstanceVariable :: (cls: *void, name: [*]u8) -> *void extern objc;
+class_getMethodImplementation :: (cls: *void, sel: *void) -> *void extern objc;
 
 SxFoo :: #objc_class("SxFoo") {
     counter: i32;

examples/1315-ffi-objc-self-class-accessor.sx

@@ -14,7 +14,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-NSObjectFwd :: #foreign #objc_class("NSObject") {
+NSObjectFwd :: #objc_class("NSObject") extern {
     alloc :: () -> *NSObjectFwd;
     init  :: (self: *NSObjectFwd) -> *NSObjectFwd;
 }

examples/1316-ffi-objc-class-method-static-imp.sx

@@ -16,7 +16,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-class_getClassMethod :: (cls: *void, sel: *void) -> *void #foreign objc;
+class_getClassMethod :: (cls: *void, sel: *void) -> *void extern objc;
 
 SxFoo :: #objc_class("SxFoo") {
     counter: i32;

examples/1317-ffi-objc-class-level-constant.sx

@@ -14,7 +14,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-NSObject :: #foreign #objc_class("NSObject") {
+NSObject :: #objc_class("NSObject") extern {
     alloc :: () -> *NSObject;
     init  :: (self: *NSObject) -> *NSObject;
 }

examples/1319-ffi-objc-property-sx-defined.sx

@@ -21,7 +21,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-class_getInstanceMethod :: (cls: *void, sel: *void) -> *void #foreign objc;
+class_getInstanceMethod :: (cls: *void, sel: *void) -> *void extern objc;
 
 SxBox :: #objc_class("SxBox") {
     width:  i32 #property;

examples/1320-ffi-objc-extends-chain.sx

@@ -12,7 +12,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-NSObjectBase :: #foreign #objc_class("NSObject") {
+NSObjectBase :: #objc_class("NSObject") extern {
     alloc :: () -> *NSObjectBase;
     init  :: (self: *NSObjectBase) -> *NSObjectBase;
     hash  :: (self: *NSObjectBase) -> u64;

examples/1321-ffi-objc-defined-class-method-self.sx

@@ -3,7 +3,7 @@
 // call site, not get truncated to i8 by the enclosing function's
 // BOOL return type. Regression locks in the
 // `resolveCallParamTypes` fix that threads foreign-class method
-// param types correctly even when the receiver is a `#foreign
+// param types correctly even when the receiver is a `extern
 // #objc_class` alias. Every probe round-trips the receiver pointer
 // — a regression would read only the low byte and the observer
 // pointer would appear as e.g. 0xC0 / 0x20 instead of its real
@@ -17,7 +17,7 @@ g_observer : *void = null;
 // Stand-in for NSNotificationCenter — we just need a foreign-class
 // method with several *void args so the call site's arg-target-type
 // resolution exercises the same path as uikit.sx's keyboard observer.
-SxIssue44Bus :: #foreign #objc_class("NSNotificationCenter") {
+SxIssue44Bus :: #objc_class("NSNotificationCenter") extern {
     defaultCenter :: () -> *SxIssue44Bus;
     addObserver_selector_name_object :: (self: *Self, observer: *void, sel: *void, name: *void, obj: *void);
 }

examples/1341-ffi-objc-dsl-01-niladic.sx

@@ -16,7 +16,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-SxProbeNiladic :: #foreign #objc_class("SxProbeNiladic") {
+SxProbeNiladic :: #objc_class("SxProbeNiladic") extern {
     length :: (self: *Self) -> i32;
 }
 

examples/1342-ffi-objc-dsl-02-one-arg.sx

@@ -8,7 +8,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-SxProbeOneArg :: #foreign #objc_class("SxProbeOneArg") {
+SxProbeOneArg :: #objc_class("SxProbeOneArg") extern {
     addObject :: (self: *Self, val: i32) -> i32;
 }
 

examples/1343-ffi-objc-dsl-03-multi-keyword.sx

@@ -7,7 +7,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-SxProbeMultiKeyword :: #foreign #objc_class("SxProbeMultiKeyword") {
+SxProbeMultiKeyword :: #objc_class("SxProbeMultiKeyword") extern {
     combine_and :: (self: *Self, a: i32, b: i32) -> i32;
 }
 

examples/1344-ffi-objc-dsl-04-mismatch.sx

@@ -8,7 +8,7 @@
 #import "modules/std.sx";
 #import "modules/build.sx";
 
-SxProbeMismatch :: #foreign #objc_class("SxProbeMismatch") {
+SxProbeMismatch :: #objc_class("SxProbeMismatch") extern {
     something_extra :: (self: *Self, x: i32) -> i32;
 }
 

examples/1345-ffi-objc-dsl-05-static.sx

@@ -15,7 +15,7 @@
 #import "modules/std.sx";
 #import "modules/build.sx";
 
-NSObject :: #foreign #objc_class("NSObject") {
+NSObject :: #objc_class("NSObject") extern {
     // `+(Class)class` — niladic, name verbatim, selector = "class".
     // Returns the class object itself. No `self: *Self` first param ⇒
     // class method (sx parser keys on the param TYPE).

examples/1346-ffi-objc-dsl-06-selector-override.sx

@@ -13,7 +13,7 @@
 #import "modules/std.sx";
 #import "modules/build.sx";
 
-NSObject :: #foreign #objc_class("NSObject") {
+NSObject :: #objc_class("NSObject") extern {
     // Default mangling would yield selector "gimme" — NSObject has no
     // such IMP. The override pins it to the real selector
     // "description". Static method (no `self: *Self` first param).
@@ -25,7 +25,7 @@ NSObject :: #foreign #objc_class("NSObject") {
 // only on this side — main only invokes the static path because we
 // don't have a real NSDictionary in scope, but the declaration locks
 // in the parser + AST + lowering wiring for the multi-arg shape.
-NSDictionary :: #foreign #objc_class("NSDictionary") {
+NSDictionary :: #objc_class("NSDictionary") extern {
     lookup :: (self: *Self, key: *void) -> *void #selector("objectForKey:");
 }
 

examples/1347-ffi-objc-dsl-07-mangling-table.sx

@@ -17,7 +17,7 @@
 #import "modules/build.sx";
 #import "modules/ffi/objc.sx";
 
-SxManglingProbe :: #foreign #objc_class("SxManglingProbe") {
+SxManglingProbe :: #objc_class("SxManglingProbe") extern {
     length                         :: (self: *Self) -> i32;
     addObject                      :: (self: *Self, a: i32) -> i32;
     combine_and                    :: (self: *Self, a: i32, b: i32) -> i32;