feat(core): add verified Russian C-SSRS Recent source content

app/core/cssrs_content.py

@@ -0,0 +1,59 @@
+"""Russian Recent source transcription, separate from the legacy sequential scale.
+
+This content does not authorize administering or continuing the questionnaire.
+Use questionnaire.score_cssrs_recent for required/missing items and risk, and
+evaluate_intake for the clinical policy gate before presenting another question.
+Never render interviewer guidance as if it were another patient question.
+"""
+
+from pathlib import Path
+from typing import Literal
+
+import yaml
+from pydantic import BaseModel, ConfigDict, Field, model_validator
+
+from app.config import get_settings
+
+ItemId = Literal["q1", "q2", "q3", "q4", "q5", "q6_lifetime", "q6_recent"]
+
+
+class SourceModel(BaseModel):
+    model_config = ConfigDict(extra="forbid", frozen=True)
+
+
+class CssrsOption(SourceModel):
+    value: int = Field(strict=True, ge=0, le=1)
+    label: str
+
+
+class CssrsItem(SourceModel):
+    id: ItemId
+    text: str = Field(min_length=1)
+    interviewer_guidance: str | None
+    recall_period: Literal["past_month", "lifetime", "past_3_months"]
+    yes_risk: Literal["low", "moderate", "high"]
+
+
+class CssrsRussianForm(SourceModel):
+    id: Literal["cssrs_recent_ru"]
+    version: str = Field(min_length=1)
+    title: str
+    subtitle: Literal["Screen Version - Recent"]
+    period_label_original: str
+    initial_instruction: str
+    branch_instruction: str
+    options: tuple[CssrsOption, CssrsOption]
+    items: tuple[CssrsItem, ...]
+
+    @model_validator(mode="after")
+    def _structure(self) -> "CssrsRussianForm":
+        if tuple(item.id for item in self.items) != ("q1", "q2", "q3", "q4", "q5", "q6_lifetime", "q6_recent"):
+            raise ValueError("Recent form requires seven ordered answer fields")
+        if tuple(option.value for option in self.options) != (1, 0):
+            raise ValueError("source answer columns are Yes, No")
+        return self
+
+
+def load_cssrs_russian(path: Path | None = None) -> CssrsRussianForm:
+    path = path or get_settings().config_dir / "instruments" / "cssrs_recent_ru.yaml"
+    return CssrsRussianForm.model_validate(yaml.safe_load(path.read_text(encoding="utf-8")))