feat(human-input): expose selected action value

[Blackoutta]

Summary

Implements the Dify-side companion for langgenius/dify#34597.

This PR exposes the selected Human Input action value in preview/editor flows and updates the Human Input UI so the right-hand field is treated as the downstream action value.

Changes

• add __action_value to Human Input preview submission outputs
• expose __action_value in Human Input output variable metadata
• update Human Input editor copy so the right-hand field is presented as Action Value
• raise the frontend action value limit from 20 to 100 while keeping the action id limit at 20
• avoid duplicate built-in variable injection by keeping Human Input built-ins in the shared workflow constants
• update backend and frontend tests

Closes #34597.

Dependency

This PR depends on the companion Graphon work:

• Graphon issue: langgenius/graphon#77
• Graphon PR: langgenius/graphon#78

Verification

uv run --project api --dev pytest ./api/tests/unit_tests/services/test_workflow_service.py -k test_submit_human_input_form_preview_success -q
pnpm exec vp test app/components/workflow/nodes/human-input/components/__tests__/user-action.spec.tsx app/components/workflow/nodes/human-input/__tests__/panel.spec.tsx app/components/workflow/nodes/human-input/__tests__/human-input.spec.tsx app/components/workflow/hooks/__tests__/use-workflow-variables.spec.ts

[github-actions]

Pyrefly Diff

base → PR

--- /tmp/pyrefly_base.txt	2026-05-10 10:25:00.471183315 +0000
+++ /tmp/pyrefly_pr.txt	2026-05-10 10:24:48.795055936 +0000
@@ -6210,11 +6210,11 @@
 ERROR `Literal['2']` is not assignable to TypedDict key `limit` with type `int` [bad-typed-dict-key]
    --> tests/unit_tests/services/test_workflow_run_service.py:132:103
 ERROR Missing required key `id` for TypedDict `NodeConfigDict` [bad-typed-dict-key]
-    --> tests/unit_tests/services/test_workflow_service.py:2747:71
+    --> tests/unit_tests/services/test_workflow_service.py:2755:71
 ERROR Missing required key `data` for TypedDict `NodeConfigDict` [bad-typed-dict-key]
-    --> tests/unit_tests/services/test_workflow_service.py:2747:71
+    --> tests/unit_tests/services/test_workflow_service.py:2755:71
 ERROR Argument `dict[str, str | dict[str, str]]` is not assignable to parameter `node_config` with type `NodeConfigDict` in function `services.workflow_service.WorkflowService._build_human_input_node` [bad-argument-type]
-    --> tests/unit_tests/services/test_workflow_service.py:2833:65
+    --> tests/unit_tests/services/test_workflow_service.py:2841:65
 ERROR Argument `Literal['api_key']` is not assignable to parameter `credential_type` with type `CredentialType` in function `services.tools.builtin_tools_manage_service.BuiltinToolManageService.list_builtin_provider_credentials_schema` [bad-argument-type]
   --> tests/unit_tests/services/tools/test_builtin_tools_manage_service.py:91:89
 ERROR Object of class `Mapping` has no attribute `startswith` [missing-attribute]

[Blackoutta]

Release-order note for reviewers: this PR depends on the companion Graphon changes in langgenius/graphon#78 / langgenius/graphon#77.

Those Graphon changes need to be merged first, and a Graphon release containing them needs to be published first. Only after Dify can consume that released Graphon version should this PR be merged and included in a Dify release.

In short: merge/release Graphon first, then merge/release this Dify PR.

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	0.00%	43.76%	+43.76%
Strict coverage	0.00%	43.29%	+43.29%
Typed symbols	0	21,998	+21,998
Untyped symbols	0	28,580	+28,580
Modules	0	2547	+2,547