chore(oss): audit the server package and resync the SDK mirrors

Split the 657-line operation service into eor, submit, and verify
modules, add the AGENT_REVOKED and KEY_RETIRED codes the Backend already
emits, and condense every multi-line comment. Mirror Node, Python, and
Go at 2.1.0 with the deep-health 503, non-idempotent retry, rotation
grace, and path-encoding fixes. Document which routes and response
fields the self-hosted server does not provide.

Claude-Session: https://claude.ai/code/session_01Agoc9bRVE9KL7mmWtey9Vq

sdks/python/elydora/plugins/hook_template.py

@@ -5,11 +5,8 @@ from __future__ import annotations
 import sys
 
 from .error_log_template import ERROR_LOG_RUNTIME
-from .guard_template import generate_guard_script
 from .runtime_reader_template import PROTECTED_RUNTIME_READER
 
-__all__ = ["generate_guard_script", "generate_hook_script"]
-
 
 def generate_hook_script(
     *,