chore: add changeset for om extractors

Co-Authored-By: Mastra Code (crof/glm-5.2) <noreply@mastra.ai>

Author: TylerBarnes

.changeset/forty-carpets-unite.md

@@ -0,0 +1,13 @@
+---
+'@mastra/memory': minor
+'@mastra/core': patch
+---
+
+add observational memory extractors
+
+Introduces a public Extractor API for Observational Memory
+with inline XML extraction and structured follow-up modes.
+Includes built-in extractors for current task, suggested
+response, and thread title. Persists extracted values into
+thread OM metadata with key-level merging and carry-forward
+into future observer/reflector prompts.