ci: add GitHub Copilot instructions

Author: BitcoinZavior

.github/copilot-instructions.md

@@ -0,0 +1,7 @@
+# Project Instructions
+Refer to the following files for coding standards, architectural patterns, and library context:
+- See [/.cursor/rules.md](/.cursor/rules.md) for core development rules.
+- See [/AGENTS.md](/AGENTS.md) for agent personas and workflows.
+- See [/llms.txt](/llms.txt) for a high-level library map.
+
+Always adhere to the schemas defined in the [/schemas/](/schemas/) directory.