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.

src/ir/inst.zig

@@ -364,7 +364,7 @@ pub const JniMsgSend = struct {
     /// NewObject(env, clazz, mid, args...)`. Returns a fresh jobject.
     /// Mutually exclusive with the other dispatch flags.
     is_constructor: bool = false,
-    /// Foreign path of the parent class (e.g. `android/app/Activity`) when
+    /// Runtime path of the parent class (e.g. `android/app/Activity`) when
     /// `is_nonvirtual` is true, OR of the class being constructed when
     /// `is_constructor` is true. emit_llvm uses `FindClass` to materialise
     /// the jclass at the call site (per-call; caching is follow-up).
@@ -508,7 +508,7 @@ pub const Function = struct {
     /// True if `params[0]` is the synthetic `__sx_ctx: *Context`
     /// parameter that every default-conv sx function receives. Callers
     /// read this flag to decide whether to prepend their current
-    /// `__sx_ctx` value to the args of a call. Foreign decls and
+    /// `__sx_ctx` value to the args of a call. Extern decls and
     /// `callconv(.c)` functions have it false.
     has_implicit_ctx: bool = false,