fix: lazy-import anthropic SDK; tolerate LLM adapter failure in dry-run mode

--dry-run was crashing with ModuleNotFoundError because:
1. adapters/llm/anthropic.py imported 'anthropic' at module level
2. TeamRunner.__init__ always built the LLM adapter regardless of dry_run flag

Fixes:
- Move 'import anthropic' inside AnthropicAdapter.__init__ (lazy import)
  so the module loads cleanly without the SDK installed
- In TeamRunner.__init__, wrap _build_llm in a try/except when dry_run=True
  so missing adapter deps are logged as warnings, not fatal errors

dry-run now works with no third-party packages installed.

adapters/llm/anthropic.py

@@ -10,8 +10,6 @@ from __future__ import annotations
 
 import os
 
-import anthropic
-
 from adapters.base.llm import LLMAdapter
 
 
@@ -57,6 +55,14 @@ class AnthropicAdapter(LLMAdapter):
         ValueError
             If ANTHROPIC_API_KEY is not set in the environment.
         """
+        try:
+            import anthropic as _anthropic
+        except ModuleNotFoundError as exc:
+            raise ImportError(
+                "The 'anthropic' package is required for AnthropicAdapter. "
+                "Install it with: pip install anthropic"
+            ) from exc
+
         self._config = config
         api_key = os.environ.get("ANTHROPIC_API_KEY")
         if not api_key:
@@ -64,7 +70,7 @@ class AnthropicAdapter(LLMAdapter):
                 "ANTHROPIC_API_KEY environment variable is not set. "
                 "Export it before running the-agency."
             )
-        self._client = anthropic.Anthropic(api_key=api_key)
+        self._client = _anthropic.Anthropic(api_key=api_key)
         self._models_cfg: dict = config.get("models", {})
         self._default_max_tokens: int = self._models_cfg.get("default_max_tokens", 4096)
         self._default_temperature: float = self._models_cfg.get("default_temperature", 0)