Fix #85: preserve dependent names when promoting to full agents

[RandomOscillations]

Summary

• ensure promoted dependents carry first_name from dependent household metadata
• preserve household last name when available for promoted dependents
• add regression test verifying promoted dependent names align with generated household dependent records

Validation

• pytest -q tests/test_agent_focus.py::TestPromotedDependentNames::test_promoted_dependents_preserve_household_names

Closes #85

[DeveshParagiri]

Code Review

Verdict: ✅ Ready to merge

Summary

Minimal 5-line fix that correctly extracts first_name from dependent metadata and preserves last_name from parent household.

Edge Cases Handled

Case	Handling
Dependent has no name	Falls back to sampled name (defensive getattr)
Household has no last_name	No override, preserves sampled value
Whitespace-only name	.strip() converts to empty, guard prevents assignment

Code

dep_name = str(getattr(dependent, "name", "")).strip()
if dep_name:
    agent["first_name"] = dep_name
if parent.get("last_name"):
    agent["last_name"] = parent["last_name"]

Tests

Regression test validates promoted dependents have names matching household metadata.

No changes required.