[P1] Flow trigger conditions with unknown functions are silently skipped (no error, passes build) #1877

Problem

A flow whose trigger condition references an unknown function is silently skipped at runtime — no error, no build failure. The automation just never fires.

Repro

Two content flows never triggered on 9.5.1:

• signal_to_topic_promotion: status == "promoted" && PRIOR(status) != "promoted" — PRIOR() not evaluated → flow skipped.
• cta_creation_default: !isBlank(record.target_channels) — isBlank() not evaluated → flow skipped.
  Rewriting to the supported previous.status / != null idioms made them fire. No log line indicated the skip.

Expected

Validate condition function names at build; at runtime, an unknown function in a condition should error loudly, not silently no-op the flow.

Affected

@objectstack/automation (condition evaluator) + build validation.

Found while runtime-testing objectstack-ai/templates (all 9 templates via objectstack dev all) on @objectstack 9.5.1. Build + typecheck pass; these only surface at runtime.