init: seed framework reference content from agent-runtimes main repo

harnesses/capabilities/tdd-file-lock/v1/harness.yaml

@@ -0,0 +1,8 @@
+kind: capability
+name: tdd-file-lock
+version: 1
+description: "Locks /workspace/tests/ read-only (root-owned). Agent cannot modify test files."
+requires: []
+
+scripts:
+  init: "./init.sh"