refonte: consolider i18n engines et nettoyer le depot

- ajoute un mode de traduction simple pour engines via engine_translate

- conserve la compatibilite apply_i18n et synchronisation automatique

- met a jour la documentation engines sur les deux approches i18n

- inclut le nettoyage global des fichiers retires

Author: raidos23

.env.example

@@ -278,6 +278,10 @@ def _debug_log(level: str, fr: str, en: str) -> None:
                 engine = create(eid)
                 # Keep instance for later interactions (i18n, etc.)
                 _INSTANCES[eid] = engine
+                try:
+                    _sync_engine_sdk_i18n(gui, eid, engine, getattr(gui, "_tr", None))
+                except Exception:
+                    pass
                 res = getattr(engine, "create_tab", None)
                 if not callable(res):
                     continue
@@ -307,6 +311,7 @@ def _debug_log(level: str, fr: str, en: str) -> None:
                 # Apply engine i18n immediately if GUI already has active translations
                 try:
                     tr = getattr(gui, "_tr", None)
+                    _sync_engine_sdk_i18n(gui, eid, engine, tr)
                     fn = getattr(engine, "apply_i18n", None)
                     if callable(fn) and isinstance(tr, dict):
                         fn(gui, tr)
@@ -362,6 +367,7 @@ def apply_translations(gui, tr: dict) -> None:
     try:
         for eid, inst in list(_INSTANCES.items()):
             try:
+                _sync_engine_sdk_i18n(gui, eid, inst, tr)
                 fn = getattr(inst, "apply_i18n", None)
                 if callable(fn) and isinstance(tr, dict):
                     fn(gui, tr)
@@ -446,6 +452,47 @@ def get_instance(eid: str) -> Optional[CompilerEngine]:
         return None
 
 
+def _engine_package_name(inst: CompilerEngine) -> str:
+    try:
+        mod = inst.__class__.__module__
+        if isinstance(mod, str) and "." in mod:
+            return mod.rsplit(".", 1)[0]
+        return str(mod)
+    except Exception:
+        return ""
+
+
+def _sync_engine_sdk_i18n(gui, eid: str, inst: CompilerEngine, tr: Optional[dict]) -> None:
+    """Populate engine_sdk simple-translate registry for engine plugins."""
+    try:
+        from engine_sdk.i18n import (
+            register_engine_translations,
+            set_engine_i18n_context,
+        )
+    except Exception:
+        return
+
+    try:
+        set_engine_i18n_context(gui, tr if isinstance(tr, dict) else None)
+    except Exception:
+        pass
+
+    try:
+        pkg = _engine_package_name(inst)
+        if not pkg:
+            return
+        code = resolve_language_code(gui, tr if isinstance(tr, dict) else None)
+        lang = load_engine_language_file(pkg, code)
+        if isinstance(lang, dict) and lang:
+            register_engine_translations(eid, lang)
+            try:
+                register_engine_translations(str(eid).lower(), lang)
+            except Exception:
+                pass
+    except Exception:
+        pass
+
+
 def create(eid: str) -> CompilerEngine:
     cls = get_engine(eid)
     if not cls: