Curvature-continuous (G2) fillets for straight planar edges (#862)

Fillet gets a Curvature (G2) radius type (type: "curvature", alias "g2"): a quintic blend whose size is the equivalent circular setback, for convex and concave straight edges between planar faces with a perpendicular planar end face at each end. Unsupported cases are refused rather than falling back to a circular fillet, and a blend that would cross a loop in its end face is refused. Persisted as a fillet style under format 19; labels in en/de/ja/ko/zh.

Co-authored-by: midasdf <[email protected]>

assets/locales/de.json

@@ -56,6 +56,8 @@
   "ui.chamfer_type": "Fasentyp",
   "ui.change_workspace": "Arbeitsbereich wechseln",
   "ui.chord_length": "Sehnenlänge",
+  "ui.curvature_g2": "Krümmungsstetig (G2)",
+  "ui.equivalent_radius": "Äquivalenter Radius",
   "ui.circle": "Kreis",
   "ui.circular_pattern": "Radiales Muster",
   "ui.clear_recent": "Zuletzt verwendet leeren",

assets/locales/en.json

@@ -328,6 +328,8 @@
   "ui.chamfer_type": "Chamfer Type",
   "ui.change_workspace": "Change workspace",
   "ui.chord_length": "Chord Length",
+  "ui.curvature_g2": "Curvature (G2)",
+  "ui.equivalent_radius": "Equivalent Radius",
   "ui.circle": "Circle",
   "ui.circular_pattern": "Circular Pattern",
   "ui.clear": "Clear",

assets/locales/ja.json

@@ -328,6 +328,8 @@
   "ui.chamfer_type": "面取りタイプ",
   "ui.change_workspace": "ワークスペースの変更",
   "ui.chord_length": "弦長",
+  "ui.curvature_g2": "曲率連続 (G2)",
+  "ui.equivalent_radius": "等価半径",
   "ui.circle": "円",
   "ui.circular_pattern": "円形パターン",
   "ui.clear": "クリア",

assets/locales/ko.json

@@ -56,6 +56,8 @@
   "ui.chamfer_type": "모따기 유형",
   "ui.change_workspace": "작업 공간 변경",
   "ui.chord_length": "현 길이",
+  "ui.curvature_g2": "곡률 연속 (G2)",
+  "ui.equivalent_radius": "등가 반지름",
   "ui.circle": "원",
   "ui.circular_pattern": "원형 패턴",
   "ui.clear_recent": "최근 항목 지우기",

assets/locales/zh.json

@@ -327,6 +327,8 @@
   "ui.chamfer_type": "倒角类型",
   "ui.change_workspace": "更改工作区",
   "ui.chord_length": "弦长",
+  "ui.curvature_g2": "曲率连续 (G2)",
+  "ui.equivalent_radius": "等效半径",
   "ui.circle": "圆",
   "ui.circular_pattern": "圆形阵列",
   "ui.clear": "清除",