feat: add per-workflow model assignment configuration

.archeflow/config.yaml

@@ -26,6 +26,30 @@ memory:
   max_lessons: 10
   decay_after_runs: 10
 
+# Models — default and per-archetype/per-workflow model selection.
+# ArcheFlow reads this to assign models to agents. The default applies unless overridden.
+models:
+  default: sonnet
+  # Per-archetype overrides (uncomment to customize):
+  # archetypes:
+  #   explorer: haiku         # Cheap model for research/exploration
+  #   creator: sonnet         # Creative tasks need stronger model
+  #   maker: sonnet           # Implementation needs full capability
+  #   guardian: sonnet        # Security review — don't skimp
+  #   skeptic: haiku          # Assumption checking is analytical
+  #   sage: haiku             # Quality review can use cheaper model
+  #   trickster: sonnet       # Adversarial testing benefits from stronger model
+  # Per-workflow overrides (uncomment to customize):
+  # workflows:
+  #   fast:
+  #     default: haiku        # Fast workflow uses cheaper models by default
+  #     archetypes:
+  #       guardian: sonnet     # Except Guardian — always needs strong model
+  #   standard:
+  #     default: sonnet
+  #   thorough:
+  #     default: sonnet
+
 # Progress
 progress:
   enabled: true