Add tests for render_report empty-evidence and Timeline branches

[shauryagangrade]

Summary

Add tests for the currently-uncovered branches of render_report in src/intent_alignment/report.py.

Why

render_report is the library's primary human-readable output, but two branches are never exercised (0% coverage per a local run):

• Empty evidence — report.py:41: lines.append(" No evidence collected.") when report.evidence is empty.
• Timeline section — report.py:62-66: rendered only when report.timeline is non-empty; the engine always produces timeline=[] (engine.py:118), so the Timeline block is currently dead code.

Both are simple to construct directly since AlignmentReport is a plain dataclass (src/intent_alignment/models.py:28-37).

Suggested approach

Add tests/unit/test_report.py:

def test_render_report_empty_evidence():
    report = AlignmentReport(overall_alignment=50.0, confidence=40.0, status="Moderate_Drift",
                             breakdown={}, summary="s", evidence=[], risk="r",
                             recommendation="rec", timeline=[])
    out = render_report(report)
    assert "No evidence collected." in out

def test_render_report_timeline():
    report = AlignmentReport(overall_alignment=50.0, confidence=40.0, status="Moderate_Drift",
                             breakdown={}, summary="s", evidence=[], risk="r",
                             recommendation="rec",
                             timeline=[{"stage": "day-1", "score": 80.0}])
    out = render_report(report)
    assert "Timeline" in out
    assert "day-1" in out

Also cover _evidence_marker thresholds (value >= 0.7, >= 0.4, else) and _format_status if convenient.

Acceptance criteria

• Both branches and the marker/format helpers are covered.
• pytest tests/ passes.