fix(bundler): resolve built-in step types when checking bundle component references

[jawwad-ali]

Problem

_resolved_locally in src/specify_cli/bundler/services/references.py gives three of the four component kinds a "is it bundled with Spec Kit?" check before the installed-in-project check. steps is the exception:

kind	bundled check	installed check
presets	_locate_bundled_preset	PresetManager(root).get_pack
extensions	_locate_bundled_extension	ExtensionManager(root).registry.is_installed
workflows	_locate_bundled_workflow	WorkflowRegistry(root).is_installed
steps	none	StepRegistry(root).is_installed

StepRegistry tracks community step types installed under .specify/workflows/steps/. Spec Kit ships 11 step types as built-ins registered in STEP_REGISTRY.

Reproduction on current main (81bf741)

built-in step types (11): ['command', 'do-while', 'fan-in', 'fan-out', 'gate',
                           'if', 'init', 'prompt', 'shell', 'switch', 'while']

_resolved_locally for a BUILT-IN step type:
  steps/shell      -> False
  steps/gate       -> False
  steps/command    -> False
  steps/if         -> False

So a bundle that declares a dependency on any built-in step type is reported as an unresolved reference — a hard error with --allow-network, a warning offline. Those are exactly the step types a bundle is most likely to depend on.

Fix

There is no _locate_bundled_step to mirror, because step types are not an on-disk asset directory — they are registered in code. STEP_REGISTRY is the bundled-with-Spec-Kit check for this kind, and it is what specify workflow step info already reports as "built-in":

from ...workflows import STEP_REGISTRY
...
if component.id in STEP_REGISTRY:
    return True
return StepRegistry(root).is_installed(component.id)

The import stays lazy and inside the function, matching every other branch. Importing specify_cli.workflows runs _register_builtin_steps(), exactly as workflow step info relies on.

No breaking change. This only makes previously-unresolvable ids resolve. A second new test pins that an unknown step id (no-such-step-type) still errors, so the guard has not made everything resolve.

Verification

• Fail-before / pass-after: test_builtin_step_type_resolves fails on unpatched src and passes with the fix. File: 1 failed → 5 passed.
• Scoped regression over tests/unit: failure set identical to the clean-main baseline captured on 81bf741 (2 pre-existing in scope).
• uvx ruff@0.15.0 check src tests → clean

Tests sit beside test_bundled_extension_resolves, the exact sibling assertion for the bundled-with-Spec-Kit case.

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Written with assistance from Claude Code. Bug found, reproduced, and verified by me on current main.