feat: add source-owned combat mechanic programs

AGENTS.md

@@ -84,6 +84,24 @@ search-oriented option sets. Preserve native form semantics, keyboard access,
 focus-visible, selected, disabled, pressed, responsive, and reduced-motion
 behavior in shared controls.
 
+## Prototype compatibility
+
+Treat application data and client payloads as prototype formats until the
+project owner declares a production-stable format. During the prototype phase:
+
+1. Prefer one current validated schema over compatibility readers, repair
+   branches, dual writes, or fallback parsing for obsolete formats.
+2. Remove incompatible local drafts, saved builds, calibration snapshots, and
+   other derived records through a backed-up migration when the current model
+   cannot represent them safely.
+3. Preserve authored game data whenever the new model can retain it without
+   guessing. Mark incomplete mechanics for configuration instead of inventing
+   trigger parameters or effect values.
+4. Follow the database-preservation rules before removing or reshaping
+   persistent data.
+5. Add compatibility support only when the project owner requires it for a
+   production-stable format.
+
 ## ISAC editor lifecycle
 
 All ISAC data-management editors must follow the same successful-save behavior: