T5: Dependency Injection — services через composition root

- AssistantService теперь принимает ForecastService в конструкторе
  (раньше создавал new ForecastService() внутри analyze/advice)
- infrastructure/cli/main.py: _build_services() — composition root,
  собирает граф ForecastService, ScenarioService, AssistantService, CurrencyConverter
- Все CLI-команды используют _build_services(model) вместо прямого new
- test_ai.py: обновлён под новый контракт AssistantService

Tests: 67/67 pass.

infrastructure/cli/main.py

@@ -42,6 +42,21 @@ def _save_model(model: FinancialModel) -> None:
     _json_repo.save(model, MODEL_PATH)
 
 
+def _build_services(model: FinancialModel):
+    """Composition root: собрать граф сервисов с зависимостями."""
+    from application.forecast import ForecastService
+    from application.scenarios import ScenarioService
+    from infrastructure.ai.assistant import AssistantService
+
+    converter = CurrencyConverter(model.exchange_rates)
+    forecast_service = ForecastService(model)
+    scenario_service = ScenarioService(model)
+    assistant_service = AssistantService(
+        model, forecast_service=forecast_service, converter=converter
+    )
+    return forecast_service, scenario_service, assistant_service, converter
+
+
 def _get_converter(model: FinancialModel) -> CurrencyConverter:
     return CurrencyConverter(model.exchange_rates)
 
@@ -81,11 +96,10 @@ def forecast(
     """Запустить прогноз денежных потоков"""
     model = _load_model()
     target_curr, symbol = _resolve_currency(model, currency)
-    converter = _get_converter(model)
+    forecast_service, _, _, converter = _build_services(model)
     base_curr = model.base_currency
-    service = ForecastService(model)
-    results = service.forecast_cashflow(months)
-    summary = service.summary(months)
+    results = forecast_service.forecast_cashflow(months)
+    summary = forecast_service.summary(months)
 
     def _cv(val):
         return _convert_value(converter, val, base_curr, target_curr)
@@ -125,9 +139,8 @@ def scenario(
     """Применить сценарий и показать прогноз"""
     model = _load_model()
     target_curr, symbol = _resolve_currency(model, currency)
-    converter = _get_converter(model)
+    _, scenario_service, _, converter = _build_services(model)
     base_curr = model.base_currency
-    service = ScenarioService(model)
 
     if name in DEFAULT_SCENARIOS:
         scenario_obj = DEFAULT_SCENARIOS[name]
@@ -136,7 +149,7 @@ def scenario(
         console.print(t("cmd.scenario.err.available", scenarios=", ".join(DEFAULT_SCENARIOS.keys())))
         raise typer.Exit(1)
 
-    result = service.apply(scenario_obj, months)
+    result = scenario_service.apply(scenario_obj, months)
     balance = _convert_value(converter, result["total_balance"], base_curr, target_curr)
     income = _convert_value(converter, result["total_income"], base_curr, target_curr)
     expenses = _convert_value(converter, result["total_expenses"], base_curr, target_curr)
@@ -158,10 +171,9 @@ def whatif(
     """What-if анализ с произвольными множителями"""
     model = _load_model()
     target_curr, symbol = _resolve_currency(model, currency)
-    converter = _get_converter(model)
+    _, scenario_service, _, converter = _build_services(model)
     base_curr = model.base_currency
-    service = ScenarioService(model)
-    result = service.what_if(income_mult, expense_mult, growth_mult, months)
+    result = scenario_service.what_if(income_mult, expense_mult, growth_mult, months)
 
     balance = _convert_value(converter, result["total_balance"], base_curr, target_curr)
     income = _convert_value(converter, result["total_income"], base_curr, target_curr)
@@ -181,10 +193,9 @@ def compare(
     """Сравнить все сценарии"""
     model = _load_model()
     target_curr, symbol = _resolve_currency(model, currency)
-    converter = _get_converter(model)
+    _, scenario_service, _, converter = _build_services(model)
     base_curr = model.base_currency
-    service = ScenarioService(model)
-    results = service.compare(months)
+    results = scenario_service.compare(months)
 
     table = Table(title=t("cmd.compare.title", currency=target_curr))
     table.add_column(t("cmd.compare.col.scenario"), style="cyan")
@@ -245,8 +256,8 @@ def analyze(
     """AI-анализ финансовой модели"""
     model = _load_model()
     target_curr, _ = _resolve_currency(model, currency)
-    converter = _get_converter(model)
-    assistant = AssistantService(model, converter=converter, display_currency=target_curr)
+    _, _, assistant, _ = _build_services(model)
+    assistant.display_currency = target_curr
     result = assistant.analyze(months)
 
     console.print(f"[bold]{t('cmd.analyze.title.prompt')}:[/bold]")