observed - UJG Spec

Goal: define an exchangeable aggregated graph derived from many executions.

This module SHOULD define (normative)

ObservedJourneyGraph minimal required fields
Aligned vs unaligned mode:
- aligned mode uses journeyRef and stateRef / transitionRef where possible
Probability definition and counting modes (and how to declare the mode)

This module SHOULD define (informative)

Time-in-state measurement approaches and limitations
How to represent unexpected transitions (violations) cleanly

Decisions to make

Do observed graphs require raw counts always (recommended) or allow only rates?
Do you allow both "all-occurrences" and "unique-per-execution" counting modes? (If yes, require explicit labeling.)

Must-align with

Runtime + Conformance (drop-off/violation semantics)
Metrics vocabulary