Joints: gears, rack and pinion, and screws (#1524)

Motion links can carry a coupling (gear pair, rack and pinion, screw) whose ratio follows radii, picked round faces or pitch. Design format 23.

Co-authored-by: SychPL <SychPL@users.noreply.github.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

assets/locales/fr.json

@@ -125,6 +125,9 @@
   "cmd.joint_limits": "Limites de liaison",
   "cmd.joint_list": "Lister les liaisons",
   "cmd.joint_motion_link": "Lien de mouvement",
+  "cmd.joint_gear": "Engrenage",
+  "cmd.joint_rack_pinion": "Pignon et crémaillère",
+  "cmd.joint_screw": "Vis",
   "cmd.joint_origin": "Origine de liaison",
   "cmd.joint_rigid_group": "Groupe rigide",
   "cmd.joint_solve": "Résoudre les liaisons",
@@ -1230,5 +1233,21 @@
   "RULED SURFACE": "SURFACE RÉGLÉE",
   "Mitre": "Onglet",
   "Reference face": "Face de référence",
-  "Round": "Arrondi"
+  "Round": "Arrondi",
+  "coupling.gear_1": "Engrenage 1",
+  "coupling.gear_2": "Engrenage 2",
+  "coupling.pinion": "Pignon",
+  "coupling.rack": "Crémaillère",
+  "coupling.nut": "Écrou",
+  "coupling.radius_1": "Rayon 1",
+  "coupling.radius_2": "Rayon 2",
+  "coupling.internal": "Engrenage intérieur",
+  "coupling.pitch": "Pas",
+  "coupling.picked": "sélectionné",
+  "coupling.not_round": "pas une face ronde",
+  "coupling.gear_1_pick": "Engrenage 1 (facultatif)",
+  "coupling.gear_2_pick": "Engrenage 2 (facultatif)",
+  "coupling.pinion_pick": "Pignon (facultatif)",
+  "coupling.needs_turns": "nécessite deux liaisons qui tournent",
+  "coupling.needs_turn_and_slide": "nécessite une liaison qui tourne et une qui glisse"
 }