feat(web): two-stage questionnaires, screening result and diary by result

- Sign-in: centred ЕМИАС card without the sidebar; anonymous entry asks «Депрессия / ПТСР».
- Stage 1 is the same for everyone and follows the fixed order of the MVP questionnaire:
  PHQ-2 → trauma filter/TSQ → RUS-AUDIT-S → C-SSRS → context; stage 2 only where stage 1
  is positive. Starts without a profile.
- After stage 1 the patient sees a preliminary result (screening, not a diagnosis), stored
  with the record; it switches on the diary modules (depression / PTSD).
- Stage 2 diary: morning (sleep, sleep quality, alcohol) and evening (mood, medication,
  3 PHQ-9 items in rotation, short PCL-5); C-SSRS since last contact only under risk;
  flags on weekly means against the personal norm; scheduled full scales with change
  (remission, response, worsening).
- Questionnaire log: GET /me/{token}/results and the «Мои результаты» screen.
- Questionnaires centred without the sidebar and without scale names; «Продолжить позже»
  goes home; confirmations are toasts; free-text comments are optional.
- Demo policy config/questionnaire_demo.yaml (INTAKE_DEMO only, not a clinical approval).

ADR-012.

Refs #77

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/core/questionnaire.py

@@ -8,6 +8,7 @@ the returned status. Pending clinical policy never authorizes routine continuati
 
 from __future__ import annotations
 
+import os
 from dataclasses import dataclass
 from datetime import datetime
 from pathlib import Path
@@ -69,8 +70,17 @@ class IntakePolicy(BaseModel):
         return self
 
 
+def demo_mode() -> bool:
+    """Demo-only switch (INTAKE_DEMO=1 with the virtual clock): questionnaires on synthetic data.
+
+    It selects `config/questionnaire_demo.yaml` (marked as NOT a clinical approval) instead of the real policy; the
+    real policy and the release gate in config/intake_runtime.yaml are never touched.
+    """
+    return os.environ.get("INTAKE_DEMO", "").lower() in ("1", "true", "yes") and get_settings().demo_clock
+
+
 def load_policy(path: Path | None = None) -> IntakePolicy:
-    path = path or get_settings().config_dir / "questionnaire.yaml"
+    path = path or get_settings().config_dir / ("questionnaire_demo.yaml" if demo_mode() else "questionnaire.yaml")
     return IntakePolicy.model_validate(yaml.safe_load(path.read_text(encoding="utf-8")))