cleanup: drop redundant @pytest.mark.asyncio + fix log_id type

- pyproject already sets asyncio_mode=auto, so async def tests are
  collected as async automatically. Removed the redundant decorator
  from four files (test_i18n, test_llm_csv_parser, test_ticker_validate,
  test_localization_integration); the bare async def is enough.
- StrategicLogTranslation.log_id used the _PK autoincrement type for
  a non-PK FK column. Replaced with a portable BigInteger that emits
  Integer on SQLite and BigInteger elsewhere — matches the migration's
  sa.BigInteger() declaration.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_localization_integration.py

@@ -55,7 +55,6 @@ def test_strategic_log_translation_model_columns():
     assert cols["content_md"].nullable is False
 
 
-@pytest.mark.asyncio
 async def test_log_translation_fanout_no_active_non_en_users(tmp_path, monkeypatch):
     """When no users have an active non-en lang, the fan-out makes no
     translation calls and no rows are inserted."""
@@ -93,7 +92,6 @@ async def test_log_translation_fanout_no_active_non_en_users(tmp_path, monkeypat
     assert rows == []
 
 
-@pytest.mark.asyncio
 async def test_log_translation_fanout_italian_user(tmp_path, monkeypatch):
     """One user at lang=it triggers one translation; the row lands with
     the right lang and log_id."""
@@ -141,7 +139,6 @@ async def test_log_translation_fanout_italian_user(tmp_path, monkeypatch):
     assert row.llm_cost_usd == pytest.approx(0.00002)
 
 
-@pytest.mark.asyncio
 async def test_log_translation_fanout_per_language_failure_isolated(tmp_path, monkeypatch):
     """If one language's translation fails, the others (if any) still land
     and the job does not raise."""
@@ -178,7 +175,6 @@ async def test_log_translation_fanout_per_language_failure_isolated(tmp_path, mo
     assert rows == []
 
 
-@pytest.mark.asyncio
 async def test_analyse_threads_lang_into_system_prompt(tmp_path, monkeypatch):
     """When lang='it', the system prompt sent to call_llm contains
     'Respond in Italian.' — the LLM does the rest."""
@@ -217,7 +213,6 @@ async def test_analyse_threads_lang_into_system_prompt(tmp_path, monkeypatch):
     assert "Respond in Italian" in system
 
 
-@pytest.mark.asyncio
 async def test_analyse_no_clause_when_lang_is_en(tmp_path, monkeypatch):
     from app.services import portfolio_analysis as pa
     from app.services.openrouter import LogResult
@@ -252,7 +247,6 @@ async def test_analyse_no_clause_when_lang_is_en(tmp_path, monkeypatch):
     assert "Respond in" not in system
 
 
-@pytest.mark.asyncio
 async def test_digest_translates_variants_per_active_lang(monkeypatch):
     """After English variants are built, the job translates each to every
     active non-en lang. The result is an in-memory mapping the send loop
@@ -294,7 +288,6 @@ async def test_digest_translates_variants_per_active_lang(monkeypatch):
     assert table[("INTERMEDIATE", "it")].startswith("[IT] ")
 
 
-@pytest.mark.asyncio
 async def test_digest_translation_failure_falls_back_to_english(monkeypatch):
     """When translate() fails for a (tone, lang) cell, the table entry
     for that cell is the English variant of the same tone — the user
@@ -334,7 +327,6 @@ def test_digest_pick_variant_uses_user_lang():
     assert ed._pick_variant(table, tone="UNKNOWN", lang="en") == "intermediate en"
 
 
-@pytest.mark.asyncio
 async def test_log_endpoint_serves_italian_when_user_is_italian(tmp_path):
     """When a user with lang='it' opens /log, the served content is the
     Italian translation, not the English original."""
@@ -370,7 +362,6 @@ async def test_log_endpoint_serves_italian_when_user_is_italian(tmp_path):
     assert "Open" not in content
 
 
-@pytest.mark.asyncio
 async def test_log_endpoint_falls_back_to_english_when_no_translation(tmp_path):
     """User lang='it' but no IT translation exists → English fallback."""
     from app.db import utcnow
@@ -397,7 +388,6 @@ async def test_log_endpoint_falls_back_to_english_when_no_translation(tmp_path):
     assert "Open" in content
 
 
-@pytest.mark.asyncio
 async def test_patch_language_accepts_active(tmp_path):
     """PATCH /api/settings/language accepts 'en' and 'it' and persists."""
     from app.models import User
@@ -428,7 +418,6 @@ async def test_patch_language_accepts_active(tmp_path):
     assert user.lang == "it"
 
 
-@pytest.mark.asyncio
 async def test_patch_language_rejects_wip(tmp_path):
     """PATCH rejects 'es'/'fr'/'de'/'xx' with 400 — ACTIVE_LANGUAGES gate."""
     from fastapi import HTTPException