chore(api): annotate simple contract responses

[hyoban]

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2. Ensure there is an associated issue and you have been assigned to it
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Summary

close #36330

Screenshots

Before	After
...	...

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	2026-05-18 10:31:53.029870873 +0000
+++ /tmp/pyrefly_pr.txt	2026-05-18 10:31:42.570770704 +0000
@@ -1,9 +1,9 @@
 ERROR `str` is not assignable to `Literal['advanced-chat', 'agent-chat', 'all', 'channel', 'chat', 'completion', 'workflow']` [bad-assignment]
-  --> controllers/console/app/app.py:69:104
+  --> controllers/console/app/app.py:70:104
 ERROR Object of class `App` has no attribute `access_mode` [missing-attribute]
-   --> controllers/console/app/app.py:583:13
+   --> controllers/console/app/app.py:585:13
 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:83:108
+  --> 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]
@@ -1830,22 +1830,6 @@
   --> tests/unit_tests/controllers/console/app/test_wraps.py:43:16
 ERROR Cannot set item in `OrderedDict[str, bool | list[str] | str]` [unsupported-operation]
    --> tests/unit_tests/controllers/console/app/workflow_draft_variables_test.py:137:47
-ERROR `None` is not subscriptable [unsupported-operation]
-   --> tests/unit_tests/controllers/console/auth/test_login_logout.py:516:16
-ERROR `None` is not subscriptable [unsupported-operation]
-   --> tests/unit_tests/controllers/console/auth/test_login_logout.py:543:16
-ERROR Object of class `tuple` has no attribute `json` [missing-attribute]
-  --> tests/unit_tests/controllers/console/auth/test_token_refresh.py:74:16
-ERROR Type `Response` is not iterable [not-iterable]
-  --> tests/unit_tests/controllers/console/auth/test_token_refresh.py:92:13
-ERROR Type `Response` is not iterable [not-iterable]
-   --> tests/unit_tests/controllers/console/auth/test_token_refresh.py:117:13
-ERROR Type `Response` is not iterable [not-iterable]
-   --> tests/unit_tests/controllers/console/auth/test_token_refresh.py:142:13
-ERROR Type `Response` is not iterable [not-iterable]
-   --> tests/unit_tests/controllers/console/auth/test_token_refresh.py:165:13
-ERROR Object of class `tuple` has no attribute `json` [missing-attribute]
-   --> tests/unit_tests/controllers/console/auth/test_token_refresh.py:192:16
 ERROR Object of class `BadRequest` has no attribute `data` [missing-attribute]
     --> tests/unit_tests/controllers/console/datasets/test_datasets.py:1655:16
 ERROR Object of class `BytesIO` has no attribute `filename` [missing-attribute]

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	0.00%	44.41%	+44.41%
Strict coverage	0.00%	43.93%	+43.93%
Typed symbols	0	22,518	+22,518
Untyped symbols	0	28,497	+28,497
Modules	0	2558	+2,558

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.97%. Comparing base (f4c02e4) to head (cd1b85d).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #36331      +/-   ##
==========================================
+ Coverage   85.94%   85.97%   +0.02%     
==========================================
  Files        4454     4455       +1     
  Lines      211503   211858     +355     
  Branches    39515    39521       +6     
==========================================
+ Hits       181782   182143     +361     
+ Misses      26509    26503       -6     
  Partials     3212     3212              

Flag	Coverage Δ
api	85.51% <100.00%> (+0.03%)	⬆️
dify-ui	94.59% <ø> (ø)
web	86.56% <ø> (+0.01%)	⬆️

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