feat(agent): configurable timeouts for auxiliary LLM calls via config.yaml (#3597)

Add per-task timeout settings under auxiliary.{task}.timeout in config.yaml
instead of hardcoded values. Users with slow local models (Ollama, llama.cpp)
can now increase timeouts for compression, vision, session search, etc.

Defaults:
  - auxiliary.compression.timeout: 120s (was hardcoded 45s)
  - auxiliary.vision.timeout: 30s (unchanged)
  - all other aux tasks: 30s (was hardcoded 30s)
  - title_generator: 30s (was hardcoded 15s)

call_llm/async_call_llm now auto-resolve timeout from config when not
explicitly passed. Callers can still override with an explicit timeout arg.

Based on PR #3406 by alanfwilliams. Converted from env vars to config.yaml
per project conventions.

Co-authored-by: alanfwilliams <alanfwilliams@users.noreply.github.com>

agent/context_compressor.py

@@ -347,7 +347,7 @@ Write only the summary body. Do not include any preamble or prefix."""
                 "messages": [{"role": "user", "content": prompt}],
                 "temperature": 0.3,
                 "max_tokens": summary_budget * 2,
-                "timeout": 45.0,
+                # timeout resolved from auxiliary.compression.timeout config by call_llm
             }
             if self.summary_model:
                 call_kwargs["model"] = self.summary_model