chore: revert #30453 FastOpenAPI

[cqjjjzr]

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Summary

Part of #30269 . FastOpenAPI is no longer on the upgrade path. For now, we are reverting them back to Flask-RESTX. Later we may upgrade them to v2 FastAPI with Frontend change.

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint && make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

[github-actions]

Pyrefly Diff

base → PR

--- /tmp/pyrefly_base.txt	2026-06-03 05:12:17.662141877 +0000
+++ /tmp/pyrefly_pr.txt	2026-06-03 05:12:03.564051984 +0000
@@ -2,18 +2,6 @@
   --> controllers/console/app/app.py:69:113
 ERROR Argument `str | None` is not assignable to parameter `language` with type `str` in function `services.account_service.AccountService.send_email_register_email` [bad-argument-type]
   --> controllers/console/auth/email_register.py:86:108
-ERROR Object of class `MissingRouter` has no attribute `get` [missing-attribute]
-  --> controllers/console/init_validate.py:31:2
-ERROR Object of class `MissingRouter` has no attribute `post` [missing-attribute]
-  --> controllers/console/init_validate.py:44:2
-ERROR Object of class `MissingRouter` has no attribute `get` [missing-attribute]
-  --> controllers/console/ping.py:10:2
-ERROR Object of class `MissingRouter` has no attribute `get` [missing-attribute]
-  --> controllers/console/setup.py:40:2
-ERROR Object of class `MissingRouter` has no attribute `post` [missing-attribute]
-  --> controllers/console/setup.py:65:2
-ERROR Object of class `MissingRouter` has no attribute `get` [missing-attribute]
-  --> controllers/console/version.py:30:2
 ERROR Class member `EasyUIBasedGenerateTaskPipeline._application_generate_entity` overrides parent class `BasedGenerateTaskPipeline` in an inconsistent manner [bad-override-mutable-attribute]
   --> core/app/task_pipeline/easy_ui_based_generate_task_pipeline.py:75:5
 ERROR `+=` is not supported between `list[PromptMessageContentUnionTypes]` and `str` [unsupported-operation]
@@ -2068,14 +2056,6 @@
    --> tests/unit_tests/controllers/console/explore/test_wraps.py:181:18
 ERROR Argument `Literal['app-id']` is not assignable to parameter `view` with type `(App) -> Unknown` in function `controllers.console.explore.wraps.decorator` [bad-argument-type]
    --> tests/unit_tests/controllers/console/explore/test_wraps.py:204:23
-ERROR Argument `Flask` is not assignable to parameter `app` with type `DifyApp` in function `extensions.ext_fastopenapi.init_app` [bad-argument-type]
-  --> tests/unit_tests/controllers/console/test_fastopenapi_ping.py:21:30
-ERROR Argument `Flask` is not assignable to parameter `app` with type `DifyApp` in function `extensions.ext_fastopenapi.init_app` [bad-argument-type]
-  --> tests/unit_tests/controllers/console/test_fastopenapi_setup.py:22:30
-ERROR Argument `Flask` is not assignable to parameter `app` with type `DifyApp` in function `extensions.ext_fastopenapi.init_app` [bad-argument-type]
-  --> tests/unit_tests/controllers/console/test_fastopenapi_setup.py:36:30
-ERROR Argument `Flask` is not assignable to parameter `app` with type `DifyApp` in function `extensions.ext_fastopenapi.init_app` [bad-argument-type]
-  --> tests/unit_tests/controllers/console/test_fastopenapi_version.py:23:30
 ERROR Argument `SimpleNamespace` is not assignable to parameter `form` with type `Form` in function `controllers.console.human_input_form._jsonify_form_definition` [bad-argument-type]
   --> tests/unit_tests/controllers/console/test_human_input_form.py:37:41
 ERROR Argument `SimpleNamespace` is not assignable to parameter `form` with type `Form` in function `controllers.console.human_input_form.ConsoleHumanInputFormApi._ensure_console_access` [bad-argument-type]

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	46.05%	46.04%	-0.01%
Strict coverage	45.55%	45.54%	-0.01%
Typed symbols	25,023	25,013	-10
Untyped symbols	29,635	29,638	+3
Modules	2790	2787	-3