feat: add default config.yaml with all documented options

.archeflow/config.yaml

@@ -0,0 +1,32 @@
+# ArcheFlow Configuration
+# Copy to your project's .archeflow/config.yaml and customize
+
+version: "0.3.0"
+
+# Budget
+costs:
+  budget_usd: 10.00
+  per_agent_usd: 2.00
+  warn_at_percent: 80
+
+# Git integration
+git:
+  enabled: true
+  branch_prefix: "archeflow/"
+  merge_strategy: squash
+  auto_push: false
+
+# Domain (auto-detected if omitted)
+# domain: code | writing | research
+
+# Memory
+memory:
+  enabled: true
+  inject_threshold: 2  # min frequency to inject
+  max_lessons: 10
+  decay_after_runs: 10
+
+# Progress
+progress:
+  enabled: true
+  file: .archeflow/progress.md