fix(workflows): reject non-list input 'enum' instead of crashing

[Noor-ul-ain001]

Problem

A workflow input whose enum is not a list slips past validation and crashes at run time:

inputs:
  scope:
    type: string
    enum: 5          # scalar instead of a list

• Runtime crash: _resolve_inputs → _coerce_input runs value not in enum_values, and x not in 5 raises a raw TypeError: argument of type 'int' is not iterable.
• Broken validator contract: the same TypeError escapes validate_workflow's except ValueError, breaking its documented "return a list of errors, never raise" contract — so authoring-time validation crashes instead of reporting an error.
• Silently-wrong string case: a bare string enum: "abc" doesn't crash but turns enum membership into a substring test (value in "abc"), silently accepting "a", "b", "ab", etc.

This is the same unvalidated-execute() crash class as #3482 (fan-in wait_for) and #3537 (fan-out step template): validate() should reject the value, but execute() accepts unvalidated definitions, so the bad value still reaches the engine.

Fix

• _coerce_input now requires enum to be a list (or None), raising a clean ValueError with a clear message for any other shape. Both the validation path and runtime resolution now fail fast.
• validate_workflow checks the enum shape directly, not only via the default-coercion path — that path only runs when a default is present, so a defaultless bad enum would otherwise slip through. A malformed enum is stripped before coercing the default so the wrong-typed-default error isn't duplicated as an enum-shape error.
• The integration: auto sentinel only strips a list enum before coercion (enum membership is a runtime concern for auto). A non-list enum stays in the definition so it's rejected rather than silently exempted.

Behavior

Before → TypeError escapes / silent substring match.
After → Input 'scope' has invalid 'enum': must be a list, got int. at both authoring and run time.

Tests

New coverage across all three layers:

• _coerce_input directly (scalar, bool, string, dict; valid list and None still work)
• validate_workflow with no default present (the path the default-coercion check misses)
• runtime _resolve_inputs
• the integration: auto interaction (non-list enum still rejected)

Full tests/test_workflows.py passes locally except the pre-existing Windows symlink-guard tests, which require elevation and are unrelated to this change.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Rejects malformed workflow input enums during validation and runtime resolution, preventing raw TypeError crashes and substring matching.

Changes:

• Enforces list-or-None enum values.
• Preserves integration: auto handling without exempting malformed enums.
• Adds validation, coercion, and runtime regression tests.

Show a summary per file

File	Description
src/specify_cli/workflows/engine.py	Validates enum shape and safely handles default coercion.
tests/test_workflows.py	Covers malformed enums across validation and runtime paths.

Review details

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• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Medium

[mnriem]

Thank you!