fix(agent): extend thinking-mode reasoning_content pad to Kimi/Moonshot

Builds on #16855 (@lsdsjy) which fixed DeepSeek v4 reasoning_content
replay via model_extra fallback + capturing tool_calls at method entry.
Kimi / Moonshot thinking mode enforces the same echo-back contract and
hits the same 400 when a tool-call turn is persisted without
reasoning_content.

- _build_assistant_message: pad branch now uses _needs_thinking_reasoning_pad()
  (DeepSeek OR Kimi) instead of _needs_deepseek_tool_reasoning() alone.
- Extract _needs_thinking_reasoning_pad() and reuse it in
  _copy_reasoning_content_for_api so both sites share one predicate.
- tests/run_agent/test_deepseek_reasoning_content_echo.py: add
  TestBuildAssistantMessagePadsStrictProviders parametrized over DeepSeek
  (attr=None, attr-absent), Kimi (attr=None), Moonshot (via base_url),
  and an OpenRouter negative control that must NOT pad. Proven to fail
  2/5 cases on Kimi/Moonshot without this change.
- scripts/release.py: add AUTHOR_MAP entries for lsdsjy and season179.

Refs #17400.

Co-authored-by: season179 <season.saw@gmail.com>

scripts/release.py

@@ -53,6 +53,9 @@ AUTHOR_MAP = {
     "sr@samirusani": "samrusani",
     "angelclaw@AngelMacBook.local": "angel12",
     "charles@cryptoassetrecovery.com": "charles-brooks",
+    # DeepSeek v4 + Kimi thinking-mode reasoning_content salvage (April 2026)
+    "luwinyang@deepseek.com": "lsdsjy",
+    "season.saw@gmail.com": "season179",
     "heathley@Heathley-MacBook-Air.local": "heathley",
     "vlad19@gmail.com": "dandaka",
     "adamrummer@gmail.com": "cyclingwithelephants",