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/1125-diagnostics-reserved-name-method-param.sx

@@ -1,7 +1,7 @@
 // A reserved/builtin type name used as a PARAMETER name is rejected inside the
 // two method-with-body forms that carry their params as bare name lists rather
 // than `Param` nodes: a protocol default-body method (`u8`) and a sx-defined
-// foreign-class (`#objc_class`) method (`i16`). The declaration-site diagnostic
+// runtime-class (`#objc_class`) method (`i16`). The declaration-site diagnostic
 // underlines the OFFENDING PARAMETER itself, not the enclosing `protocol` /
 // `#objc_class` block — each method's `param_name_spans` is threaded from the
 // parser so the caret lands on the parameter token.