Scenario validator ignores extended_attributes when resolving attribute references

[RandomOscillations]

Summary

validate_scenario() builds known_attributes from the base population spec only, and does not add ScenarioSpec.extended_attributes. This causes invalid validation behavior for scenario conditions that legitimately reference extended attributes.

Why This Matters

In the study-folder flow, sampling merges base + extended attributes before generating agents. Scenario rules should be validated against the same effective attribute namespace used downstream. Current mismatch creates false negatives and brittle authoring.

Current Behavior (Code)

In /Users/adithyasrinivasan/Projects/extropy/extropy/scenario/validator.py:

• known_attributes is initialized from population_spec.attributes only (line ~120-123)
• references in seed_exposure.rules[].when and spread.share_modifiers[].when are checked against that base-only set (line ~218, line ~295)
• spec.extended_attributes is not included anywhere in the reference set

Expected Behavior

Attribute reference validation should use:

• base population attributes
• PLUS scenario extended_attributes

Proposed Fix

1. Build known_attributes as:

• base attr names from population_spec (if present)
• union with {a.name for a in spec.extended_attributes or []}

2. Apply this unified set to all expression-reference checks in scenario validator.

3. Add tests:

• scenario with extended_attributes=[foo_bar], and a when clause referencing foo_bar should pass
• unknown attr should still fail

Acceptance Criteria

• Valid references to extended attributes no longer fail validation.
• Unknown references still produce errors.
• Behavior is consistent across extropy validate and compile/load validation paths.

Pipeline Impact

Steps 2->3 consistency (scenario -> sample) improves by aligning validator namespace with merged-spec sampling behavior.

[RandomOscillations]

Implemented on branch codex/steps1-3-hardening (see PR #124). Keeping this issue open until merge + integration verification completes.

[RandomOscillations]

Closing as fixed. Scenario validation now resolves attribute references against merged base + . See and downstream validators in .