test(strategy_crypto): smoke regression + import-mode importlib per workspace

NEW src/strategy_crypto/tests/test_imports.py:
- test_backend_imports — verifica re-export PaperExecutor/Portfolio/PaperRepository + schema
- test_frontend_imports — strategy_crypto.frontend.{data,nicegui_app} importabili
- test_strategies_json_loadable — i JSON sono in importlib.resources e ben formati
- test_init_schema_creates_tables — PaperRepository.init_schema() crea 5 tabelle

Fix pytest collection: add --import-mode=importlib agli addopts per evitare
collisione dei due tests/__init__.py (core + strategy_crypto) sotto stesso
nome module 'tests'.

Verifica: uv run pytest → 186 passed (182 core + 4 strategy_crypto)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/strategy_crypto/tests/test_imports.py

@@ -0,0 +1,67 @@
+"""Smoke regression: il package strategy_crypto importa senza errori
+e i JSON freezate sono accessibili via importlib.resources.
+
+Sostituisce la responsabilita' di un test di integrazione: serve solo
+a catturare regressioni di import/packaging dopo refactor cross-modulo.
+"""
+
+from __future__ import annotations
+
+import importlib.resources
+import json
+
+
+def test_backend_imports() -> None:
+    from strategy_crypto.backend import (
+        PaperExecutor,
+        PaperRepository,
+        Portfolio,
+    )
+    from strategy_crypto.backend.schema import PAPER_SCHEMA_SQL, init_schema
+
+    assert PaperExecutor.__name__ == "PaperExecutor"
+    assert PaperRepository.__name__ == "PaperRepository"
+    assert Portfolio.__name__ == "Portfolio"
+    assert "CREATE TABLE" in PAPER_SCHEMA_SQL
+    assert callable(init_schema)
+
+
+def test_frontend_imports() -> None:
+    import strategy_crypto.frontend.data  # noqa: F401
+    import strategy_crypto.frontend.nicegui_app  # noqa: F401
+
+
+def test_strategies_json_loadable() -> None:
+    files = importlib.resources.files("strategy_crypto") / "strategies"
+    found = sorted(p.name for p in files.iterdir() if p.name.endswith(".json"))
+    assert "btc_fb63e851.json" in found
+    assert "eth_facd6af85d5d.json" in found
+    for fname in found:
+        data = json.loads((files / fname).read_text())
+        assert "rules" in data, f"{fname} missing 'rules' key"
+        assert isinstance(data["rules"], list)
+
+
+def test_init_schema_creates_tables(tmp_path) -> None:
+    import sqlite3
+
+    from strategy_crypto.backend.schema import init_schema
+
+    db = tmp_path / "paper.db"
+    init_schema(db)
+    conn = sqlite3.connect(str(db))
+    try:
+        rows = conn.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' AND name LIKE 'paper_%'"
+        ).fetchall()
+        names = {r[0] for r in rows}
+    finally:
+        conn.close()
+    expected = {
+        "paper_trading_runs",
+        "paper_trading_positions",
+        "paper_trading_trades",
+        "paper_trading_equity",
+        "paper_trading_ticks",
+    }
+    assert expected.issubset(names), f"missing tables: {expected - names}"