feat(recipes): add manual checkpoint reconnect for broken recipe entries

Checkpoint entries that cannot be restored by download (deleted,
unresolvable hash, or name-only remnants with no CivitAI identifiers)
now get the same remediation chain LoRAs already had:

- scanner: parameterized reconnect-suggestion ranking, update/restore/
  set-hash-invalid for the checkpoint entry, and clear hashInvalid on
  rematch write-back (was only done for LoRAs)
- persistence/handlers/routes: reconnect/restore/reconnect-suggestions/
  mark-hash-invalid endpoints under /api/lm/recipe/checkpoint/*
- modal: checkpoint reconnect UI (deleted/hash-invalid badges, inline
  form with suggestions, undo for reconnected entries); download
  failures mark the hash invalid only on explicit unresolvable signals
  (not found/deleted/404/410), matching the LoRA rule
- css: checkpoint undo button shares the LoRA undo styles
- i18n: the 14 new keys translated in all 9 locales

py/routes/handlers/recipe_handlers.py

@@ -116,6 +116,10 @@ class RecipeHandlerSet:
             "restore_lora": self.management.restore_lora,
             "get_reconnect_suggestions": self.management.get_reconnect_suggestions,
             "mark_lora_hash_invalid": self.management.mark_lora_hash_invalid,
+            "reconnect_checkpoint": self.management.reconnect_checkpoint,
+            "restore_checkpoint": self.management.restore_checkpoint,
+            "get_checkpoint_reconnect_suggestions": self.management.get_checkpoint_reconnect_suggestions,
+            "mark_checkpoint_hash_invalid": self.management.mark_checkpoint_hash_invalid,
             "find_duplicates": self.query.find_duplicates,
             "move_recipes_bulk": self.management.move_recipes_bulk,
             "bulk_delete": self.management.bulk_delete,
@@ -1683,6 +1687,116 @@ class RecipeManagementHandler:
             )
             return web.json_response({"error": str(exc)}, status=500)
 
+    async def reconnect_checkpoint(self, request: web.Request) -> web.Response:
+        try:
+            await self._ensure_dependencies_ready()
+            recipe_scanner = self._recipe_scanner_getter()
+            if recipe_scanner is None:
+                raise RuntimeError("Recipe scanner unavailable")
+
+            data = await request.json()
+            for field in ("recipe_id", "target_name"):
+                if field not in data:
+                    raise RecipeValidationError(f"Missing required field: {field}")
+
+            result = await self._persistence_service.reconnect_checkpoint(
+                recipe_scanner=recipe_scanner,
+                recipe_id=data["recipe_id"],
+                target_name=data["target_name"],
+            )
+            return web.json_response(result.payload, status=result.status)
+        except RecipeValidationError as exc:
+            return web.json_response({"error": str(exc)}, status=400)
+        except RecipeNotFoundError as exc:
+            return web.json_response({"error": str(exc)}, status=404)
+        except Exception as exc:
+            self._logger.error(
+                "Error reconnecting checkpoint: %s", exc, exc_info=True
+            )
+            return web.json_response({"error": str(exc)}, status=500)
+
+    async def restore_checkpoint(self, request: web.Request) -> web.Response:
+        try:
+            await self._ensure_dependencies_ready()
+            recipe_scanner = self._recipe_scanner_getter()
+            if recipe_scanner is None:
+                raise RuntimeError("Recipe scanner unavailable")
+
+            data = await request.json()
+            if "recipe_id" not in data:
+                raise RecipeValidationError("Missing required field: recipe_id")
+
+            result = await self._persistence_service.restore_checkpoint(
+                recipe_scanner=recipe_scanner,
+                recipe_id=data["recipe_id"],
+            )
+            return web.json_response(result.payload, status=result.status)
+        except RecipeValidationError as exc:
+            return web.json_response({"error": str(exc)}, status=400)
+        except RecipeNotFoundError as exc:
+            return web.json_response({"error": str(exc)}, status=404)
+        except Exception as exc:
+            self._logger.error("Error restoring checkpoint: %s", exc, exc_info=True)
+            return web.json_response({"error": str(exc)}, status=500)
+
+    async def get_checkpoint_reconnect_suggestions(
+        self, request: web.Request
+    ) -> web.Response:
+        try:
+            await self._ensure_dependencies_ready()
+            recipe_scanner = self._recipe_scanner_getter()
+            if recipe_scanner is None:
+                raise RuntimeError("Recipe scanner unavailable")
+
+            recipe_id = request.match_info.get("recipe_id")
+            if not recipe_id:
+                raise RecipeValidationError("recipe_id is required")
+
+            result = await self._persistence_service.get_checkpoint_reconnect_suggestions(
+                recipe_scanner=recipe_scanner,
+                recipe_id=recipe_id,
+                query=request.query.get("query") or None,
+            )
+            return web.json_response(result.payload, status=result.status)
+        except RecipeValidationError as exc:
+            return web.json_response({"error": str(exc)}, status=400)
+        except RecipeNotFoundError as exc:
+            return web.json_response({"error": str(exc)}, status=404)
+        except Exception as exc:
+            self._logger.error(
+                "Error suggesting checkpoint reconnect candidates: %s",
+                exc,
+                exc_info=True,
+            )
+            return web.json_response({"error": str(exc)}, status=500)
+
+    async def mark_checkpoint_hash_invalid(self, request: web.Request) -> web.Response:
+        try:
+            await self._ensure_dependencies_ready()
+            recipe_scanner = self._recipe_scanner_getter()
+            if recipe_scanner is None:
+                raise RuntimeError("Recipe scanner unavailable")
+
+            data = await request.json()
+            if "recipe_id" not in data:
+                raise RecipeValidationError("Missing required field: recipe_id")
+
+            result = await self._persistence_service.mark_checkpoint_hash_invalid(
+                recipe_scanner=recipe_scanner,
+                recipe_id=data["recipe_id"],
+                hash_invalid=bool(data.get("hash_invalid", True)),
+            )
+            return web.json_response(result.payload, status=result.status)
+        except RecipeValidationError as exc:
+            return web.json_response({"error": str(exc)}, status=400)
+        except RecipeNotFoundError as exc:
+            return web.json_response({"error": str(exc)}, status=404)
+        except Exception as exc:
+            self._logger.error(
+                "Error marking checkpoint hash invalid: %s", exc, exc_info=True
+            )
+            return web.json_response({"error": str(exc)}, status=500)
+
     async def bulk_delete(self, request: web.Request) -> web.Response:
         try:
             await self._ensure_dependencies_ready()