docs: add Trellis planning and project specs

.trellis/scripts/get_context.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+"""
+Get Session Context for AI Agent.
+
+Usage:
+    python3 get_context.py           Output context in text format
+    python3 get_context.py --json    Output context in JSON format
+"""
+
+from __future__ import annotations
+
+from common.git_context import main
+
+
+if __name__ == "__main__":
+    main()