fix: resolve import migrations and test failures after segment 3 merge

- Migrate core.model_runtime -> dify_graph.model_runtime across 20+ files
- Migrate core.workflow.file -> dify_graph.file across 15+ files
- Migrate core.workflow.enums -> dify_graph.enums in service files
- Fix SandboxContext phantom import in dify_graph/context/__init__.py
- Fix core.app.workflow.node_factory -> core.workflow.node_factory
- Fix toast import paths (useToastContext from toast/context)
- Fix app-info.tsx import paths for relocated app-operations
- Fix 15 frontend test files for API changes, missing QueryClientProvider,
  i18n key renames, and component behavior changes

Made-with: Cursor

api/core/agent/patterns/react.py

@@ -9,7 +9,7 @@ from typing import TYPE_CHECKING, Any, Union
 from core.agent.entities import AgentLog, AgentResult, AgentScratchpadUnit, ExecutionContext
 from core.agent.output_parser.cot_output_parser import CotAgentOutputParser
 from core.model_manager import ModelInstance
-from core.model_runtime.entities import (
+from dify_graph.model_runtime.entities import (
     AssistantPromptMessage,
     LLMResult,
     LLMResultChunk,
@@ -17,7 +17,7 @@ from core.model_runtime.entities import (
     PromptMessage,
     SystemPromptMessage,
 )
-from core.workflow.file import File
+from dify_graph.file import File
 
 from .base import AgentPattern, ToolInvokeHook
 
@@ -204,7 +204,7 @@ class ReActStrategy(AgentPattern):
                     tool_names = [tool.name for tool in prompt_tools]
 
                     # Format tools as JSON for comprehensive information
-                    from core.model_runtime.utils.encoders import jsonable_encoder
+                    from dify_graph.model_runtime.utils.encoders import jsonable_encoder
 
                     tools_str = json.dumps(jsonable_encoder(prompt_tools), indent=2)
                     tool_names_str = ", ".join(f'"{name}"' for name in tool_names)