fix: standardize on file extension .yaml instead of a mix of yml and yaml

bmad-core/core-config.yaml

@@ -0,0 +1,25 @@
+version: 4.21.1
+markdownExploder: true
+prd:
+  prdFile: docs/prd.md
+  prdVersion: v4
+  prdSharded: true
+  prdShardedLocation: docs/prd
+  epicFilePattern: epic-{n}*.md
+architecture:
+  architectureFile: docs/architecture.md
+  architectureVersion: v4
+  architectureSharded: true
+  architectureShardedLocation: docs/architecture
+customTechnicalDocuments: null
+devLoadAlwaysFiles:
+  - docs/architecture/coding-standards.md
+  - docs/architecture/tech-stack.md
+  - docs/architecture/source-tree.md
+devDebugLog: .ai/debug-log.md
+devStoryLocation: docs/stories
+workflow:
+  planFile: docs/workflow-plan.md
+  trackProgress: true
+  enforceSequence: false
+  updateOnCompletion: true