refactor(ffi-linkage): Phase 9.3 — purge 'foreign' from comments (src caps + examples + docs)

src/: ~21 capital-Foreign comments the case-sensitive verify grep missed
(Foreign-class→Runtime-class, Foreign path→Runtime path, Foreign decls→Extern decls,
FOREIGN function→extern function) across calls/inst/ffi_objc/jni_descriptor/emit_llvm/
c_import/lower.*/ops. src 'foreign' now = ONLY the hash_foreign token + 4 rejection
messages (9.0-delete targets). examples/*.sx comments → extern/runtime-class (1219
stdout regen; KEPT 1176). docs/inline-asm-design + debugger purged. Comments only —
no build impact. 9.0 ratified: DELETE hash_foreign token next.

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

@@ -1,13 +1,13 @@
-// Chained foreign-class method dispatch: `Cls.static().instance(...)`
+// Chained runtime-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 i64 in
-// `inferExprType`, the foreign_class_map lookup missed, and lowering
+// `inferExprType`, the runtime_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.
+// next `.method(...)` finds the runtime-class declaration.
 
 #import "modules/std.sx";
 #import "modules/build.sx";