T6: Decompose CLI — main.py → 9 command files, config.py → config_cmd.py

Split infrastructure/cli/:
- main.py (330 LOC) → 9 files in infrastructure/cli/commands/:
  * init.py, forecast.py, scenario.py, whatif.py, compare.py
  * import_xlsx.py, export_xlsx.py, analyze.py, info.py
- config.py (428 LOC) → commands/config_cmd.py (15 sub-commands)
- main.py → app.py (entry point: registers all commands)
- New: paths.py (MODEL_PATH, DATA_DIR)
- New: services.py (composition root + helpers: load_model, save_model,
  build_services, resolve_currency, convert_value, fmt_amount)
- cli/__init__.py (empty) удалён

Each command module: <100 LOC.
pyproject.toml: cf = infrastructure.cli.app:app
tests/test_cli.py: import обновлён на infrastructure.cli.app

CLI behavior идентично, все команды работают.
Tests: 67/67 pass.

infrastructure/cli/commands/export_xlsx.py

@@ -0,0 +1,23 @@
+"""cf export-xlsx — экспорт модели в Excel."""
+import typer
+
+from infrastructure.cli.i18n import t
+from infrastructure.cli.services import console, load_model
+from infrastructure.repositories import ExcelRepository, ExcelRepositoryError
+
+app = typer.Typer()
+_repo = ExcelRepository()
+
+
+@app.command(name="export-xlsx")
+def export_xlsx(
+    path: str = typer.Argument("exports/forecast.xlsx", help=t("cmd.export.arg.path")),
+) -> None:
+    """Экспорт модели в Excel"""
+    model = load_model()
+    try:
+        _repo.save(model, path)
+        console.print(t("cmd.export.ok", path=path))
+    except ExcelRepositoryError as e:
+        console.print(f"[red]{t('cmd.export.err', error=str(e))}[/red]")
+        raise typer.Exit(1)