fix(code-runtime-python): write dispatch frames through def-time bound primitives

The review's remaining functional item: send_sync's body resolves
_encode_json_plain (module global) and self.write_encoded (class attribute) at
call time, so a program rebinding either before the first binding call could
turn a legitimate call into an exception. dispatch now writes the call frame
through def-time bound write_encoded+_encode_json_plain, and the log sink goes
through the bound send; the dispatch rebind test also rebinds those two names
(verified fail-before by reverting to send_sync). The annotation test title
matches its assertion direction, and the note (en + zh) registers the
error-class constructor, dispatch primitives, and dont_inherit mechanisms.
Pairing re-recorded.

packages/code-runtime/code-runtime-python/tests/runtime.spec.ts

@@ -711,6 +711,8 @@ describe('PythonCodeRuntime — programs and bindings', () => {
         '__main__._lossless_json_violation = boom',
         '__main__.asyncio = boom',
         '__main__.ProtocolChannel.send_sync = boom',
+        '__main__._encode_json_plain = boom',
+        '__main__.ProtocolChannel.write_encoded = boom',
         'first = await tools.echo({"n": 1})',
         'return first',
       ].join('\n'),
@@ -2745,7 +2747,7 @@ describe('PythonCodeRuntime — budgets, termination, disposal', () => {
     expect(result.value).toBe("read: ''")
   }, 15_000)
 
-  it('keeps runtime type annotations unevaluated-as-strings when the program reads them', async () => {
+  it('keeps runtime type annotations as live classes, not PEP 563 strings, when the program reads them', async () => {
     // bootstrap.py imports `from __future__ import annotations`; without
     // dont_inherit=True on compile(), that PEP 563 flag leaks into the program's
     // compiled code and stringifies its type annotations, changing the semantics