feat(automation): resolve & validate script-node callables; function registration (#1870)

[os-zhuang]

Closes#1870.

Problem

A flow script/action node pointing at an unregistered callable (invoke_function → a function defined nowhere), or declaring no actionType/function at all (actionType: undefined), built + typechecked fine and then silently did nothing at runtime. There was also no first-class way for an authored package to register a function a script node could call. Found while runtime-testing objectstack-ai/templates on 9.5.1 (helpdesk ai_triage_on_create → helpdesk.aiTriageStub; project daily_ai_risk_assessment → pm.aiRiskAssessmentStub; content publication_rollup with actionType: undefined).

Fix

Three surfaces, mirroring the loud-validation approach from #1877:

1. Loud runtime resolution — screen-nodes.ts
The built-in script executor resolves its target in order:

• built-in side-effect (email/slack, logger-backed, preserved) →
• a registered function (config.function, or a bare config.actionType that matches no built-in, so a node pointed straight at helpdesk.aiTriageStub resolves) →
• otherwise fail the step loudly.

The old [Script:…] (no-op handler) → { success: true } path is gone.

2. First-class registration path — engine.ts + plugin.ts
New AutomationEngine.setFunctionResolver() / resolveFunction(). The plugin's start() bridges it to ObjectQL's resolveFunction, populated from bundle.functions / defineStack({ functions }) — the same registry hooks/actions already use. So an authored package registers a function and calls it from a flow:

// defineStack({ functions: { 'helpdesk.aiTriageStub': (ctx) => ({ priority: 'high' }) }}){type: 'script',config: {function: 'helpdesk.aiTriageStub',inputs: {ticket: '{record.id}'}}}

The function receives { input, variables, automation, logger } and its return value becomes the node output. Reuses the existing script node (no enum/Studio churn) per the chosen authoring contract.

3. Build-time structural check — validate-expressions.ts
objectstack build now flags a script node that declares neither actionType nor function (the actionType: undefined repro). Function existence is not checkable at build — functions are code, not serialized into the artifact — so existence is enforced at runtime.

Design note

Registration-time (registerFlow) does not hard-fail on a target-less script node: a script node can be claimed by a plugin-registered custom executor (existing engine tests rely on this), and the engine can't distinguish built-in vs custom at registration. The guard lives where it's unambiguous — the built-in executor (runtime) and objectstack build (authored metadata).

Tests

• New screen-nodes.test.ts: built-in side-effect, function resolution + output capture, bare-actionType shorthand, loud failure for unregistered function, loud failure for no target, thrown-function surfacing.
• validate-expressions.test.ts: build flags target-less script node; accepts actionType/function.
• @objectstack/service-automation 193 passed · @objectstack/cli 260 passed · production build + DTS clean (the package's pre-existing tsc --noEmit test-fixture errors are unrelated and present on main).

Scope

Slice A (loud validation) + Slice B (registration path) per the issue. connector_action already failed loud and is unchanged.

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Project	Deployment	Actions	Updated (UTC)
spec	Ready	Preview, Comment	Jun 15, 2026 9:32am