Closing gaps and cleaning house

internal/topdata/FEAT_GENERATED_FAMILIES_CONTRACT.md

@@ -86,6 +86,7 @@ Weapon family shape:
   "name_prefix": "Weapon Focus",
   "label_prefix": "FEAT_WEAPON_FOCUS",
   "constant_prefix": "FEAT_WEAPON_FOCUS",
+  "legacy_family_keys": ["epic_weapon_focus"],
   "default_fields": {
     "DESCRIPTION": {
       "tlk": {
@@ -123,6 +124,10 @@ Rules:
 - `apply_after_modules: true` makes the generated family the final authoritative shared
   layer for legacy explicitly authored child rows, so shared baselines can live in the
   generated family file instead of `masterfeats` overrides
+- `legacy_family_keys` declares old generated-family prefixes whose existing row IDs
+  should be inherited by the current family; this is how renamed families such as
+  `greater_skill_focus` retaining vanilla `epic_skill_focus` rows preserve hardcoded
+  engine behavior without hardcoding the rename in toolkit logic
 - family-expansion files must declare `template`, `family_key`, and `child_source.dataset`
 - `child_source.column` is used when expansion is gated by a non-null source field
 - `child_source.predicate: "accessible"` currently means `HideFromLevelUp != 1`