fix(kimi): omit temperature entirely for Kimi/Moonshot models (#13157)

Kimi's gateway selects the correct temperature server-side based on the
active mode (thinking -> 1.0, non-thinking -> 0.6).  Sending any
temperature value — even the previously "correct" one — conflicts with
gateway-managed defaults.

Replaces the old approach of forcing specific temperature values (0.6
for non-thinking, 1.0 for thinking) with an OMIT_TEMPERATURE sentinel
that tells all call sites to strip the temperature key from API kwargs
entirely.

Changes:
- agent/auxiliary_client.py: OMIT_TEMPERATURE sentinel, _is_kimi_model()
  prefix check (covers all kimi-* models), _fixed_temperature_for_model()
  returns sentinel for kimi models.  _build_call_kwargs() strips temp.
- run_agent.py: _build_api_kwargs, flush_memories, and summary generation
  paths all handle the sentinel by popping/omitting temperature.
- trajectory_compressor.py: _effective_temperature_for_model returns None
  for kimi (sentinel mapped), direct client calls use kwargs dict to
  conditionally include temperature.
- mini_swe_runner.py: same sentinel handling via wrapper function.
- 6 test files updated: all 'forces temperature X' assertions replaced
  with 'temperature not in kwargs' assertions.

Net: -76 lines (171 added, 247 removed).
Inspired by PR #13137 (@kshitijk4poor).

tests/test_trajectory_compressor_async.py

@@ -117,7 +117,8 @@ class TestSourceLineVerification:
 
 
 @pytest.mark.asyncio
-async def test_generate_summary_async_custom_client_forces_kimi_temperature():
+async def test_generate_summary_async_kimi_omits_temperature():
+    """Kimi models should have temperature omitted — server manages it."""
     from trajectory_compressor import CompressionConfig, TrajectoryCompressor, TrajectoryMetrics
 
     config = CompressionConfig(
@@ -140,11 +141,12 @@ async def test_generate_summary_async_custom_client_forces_kimi_temperature():
     result = await compressor._generate_summary_async("tool output", metrics)
 
     assert result.startswith("[CONTEXT SUMMARY]:")
-    assert async_client.chat.completions.create.call_args.kwargs["temperature"] == 0.6
+    assert "temperature" not in async_client.chat.completions.create.call_args.kwargs
 
 
 @pytest.mark.asyncio
-async def test_generate_summary_async_public_moonshot_kimi_k2_5_forces_temperature_1():
+async def test_generate_summary_async_public_moonshot_kimi_k2_5_omits_temperature():
+    """kimi-k2.5 on the public Moonshot API should not get a forced temperature."""
     from trajectory_compressor import CompressionConfig, TrajectoryCompressor, TrajectoryMetrics
 
     config = CompressionConfig(
@@ -168,12 +170,12 @@ async def test_generate_summary_async_public_moonshot_kimi_k2_5_forces_temperatu
     result = await compressor._generate_summary_async("tool output", metrics)
 
     assert result.startswith("[CONTEXT SUMMARY]:")
-    assert async_client.chat.completions.create.call_args.kwargs["temperature"] == 1.0
-
+    assert "temperature" not in async_client.chat.completions.create.call_args.kwargs
 
 
 @pytest.mark.asyncio
-async def test_generate_summary_async_public_moonshot_cn_kimi_k2_5_forces_temperature_1():
+async def test_generate_summary_async_public_moonshot_cn_kimi_k2_5_omits_temperature():
+    """kimi-k2.5 on api.moonshot.cn should not get a forced temperature."""
     from trajectory_compressor import CompressionConfig, TrajectoryCompressor, TrajectoryMetrics
 
     config = CompressionConfig(
@@ -197,4 +199,4 @@ async def test_generate_summary_async_public_moonshot_cn_kimi_k2_5_forces_temper
     result = await compressor._generate_summary_async("tool output", metrics)
 
     assert result.startswith("[CONTEXT SUMMARY]:")
-    assert async_client.chat.completions.create.call_args.kwargs["temperature"] == 1.0
+    assert "temperature" not in async_client.chat.completions.create.call_args.kwargs