docs(maintenance): add goals section (#23328)

Add a project goals section to MAINTENANCE.md.

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MAINTENANCE.md

@@ -1,3 +1,12 @@
+## Goals
+
+In no specific order:
+
+- Better performance
+- Lower memory usage
+- More test coverage
+- Better conformance with existing tools and specifications
+
 ## Oxlint & Oxfmt
 
 ### Release Oxlint & Oxfmt