fix(legendas): impede legenda comum sob composição dinâmica e duplicação ao regerar

Marca cada título gerado (dynamic/plain) em metadata para que regenerar
substitua a saída anterior em vez de empilhar, e usa os spans de ênfase
revisados (não os segmentos brutos do Whisper) como janela da composição
dinâmica, evitando que ela invada o trecho de legenda comum seguinte.
suppress_plain_under_dynamic corta qualquer sobra visível como rede de
segurança.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

code/tests/test_subtitle_overlap_regression.py

@@ -0,0 +1,72 @@
+"""Exercise the real subtitle handler across emphasis gaps and regeneration."""
+
+import asyncio
+from pathlib import Path
+
+import pytest
+
+from fcpxml.models import DynamicSubtitleConfig
+from fcpxml.writer import FCPXMLModifier
+from server_tools import subtitles
+
+
+@pytest.fixture
+def caption_job(tmp_path, monkeypatch):
+    modifier = FCPXMLModifier(Path(__file__).parents[1] / "examples/sample.fcpxml")
+    parent = modifier._require_clip("Interview_A")
+    parent.set("start", "0s")
+    parent.set("duration", "10s")
+    media = tmp_path / "speech.mov"
+    media.touch()
+    modifier.resources[parent.get("ref")]["src"] = media.as_uri()
+    monkeypatch.setattr(modifier, "_iter_spine_clips", lambda: iter([(0, parent)]))
+    monkeypatch.setattr(subtitles, "_setup_modifier", lambda *args: (
+        "input.fcpxml", str(tmp_path / "output.fcpxml"), modifier,
+    ))
+    monkeypatch.setattr(subtitles, "get_active_dynamic_subtitle_layouts", lambda: [
+        {"role": "titles.dinamicas"},
+    ])
+    monkeypatch.setattr(subtitles, "_build_dynamic_subtitle_config", lambda *args: DynamicSubtitleConfig())
+    monkeypatch.setattr(subtitles, "load_plain_subtitle_config", lambda: {
+        "role": "titles.convencionais", "font": "Helvetica Neue", "font_size": 48,
+        "font_color": "1 1 1 1", "max_words": 1, "position_y": -100,
+        "uppercase": False, "keep_punctuation": True,
+    })
+    monkeypatch.setattr(subtitles, "_load_plain_exclude_spans", lambda _: [])
+    monkeypatch.setattr(subtitles, "_load_emphasis_spans", lambda _: [
+        {"start": 0, "end": 1}, {"start": 4, "end": 5},
+    ])
+    monkeypatch.setattr(subtitles, "_load_or_transcribe", lambda *args: ({
+        "words": [
+            {"word": "corpo", "start": 0, "end": 1},
+            {"word": "muda", "start": 2, "end": 3},
+            {"word": "também", "start": 4, "end": 5},
+        ],
+        "segments": [{"start": 0, "end": 1}, {"start": 4, "end": 5}],
+    }, None))
+    return modifier, parent
+
+
+def test_dynamic_composition_clears_before_plain_words_in_emphasis_gap(caption_job):
+    modifier, parent = caption_job
+    asyncio.run(subtitles.handle_generate_subtitles_by_emphasis({}))
+    dynamic = parent.findall("ref-clip")
+    plain = parent.findall("title")
+    assert dynamic and plain
+    for composition in dynamic:
+        start = modifier._parse_time(composition.get("offset"))
+        end = start + modifier._parse_time(composition.get("duration"))
+        for title in plain:
+            plain_start = modifier._parse_time(title.get("offset"))
+            plain_end = plain_start + modifier._parse_time(title.get("duration"))
+            assert not (start < plain_end and plain_start < end), "dynamic and plain overlap"
+
+
+def test_regeneration_replaces_generated_subtitles_and_preserves_manual_titles(caption_job):
+    modifier, parent = caption_job
+    manual = modifier.add_text_title(parent, "Nome da médica", role="titles.manual")
+    asyncio.run(subtitles.handle_generate_subtitles_by_emphasis({}))
+    initial = len(parent.findall("ref-clip")) + len(parent.findall("title"))
+    asyncio.run(subtitles.handle_generate_subtitles_by_emphasis({}))
+    assert len(parent.findall("ref-clip")) + len(parent.findall("title")) == initial
+    assert manual in list(parent)