feat(oracle): auto-recover Oracle pool + surface status, stop silent import failures

After a power loss the app started before Oracle was ready; init_oracle() failed
once, the pool stayed None forever (no retry), and every sync silently failed
("Oracle pool not initialized") while still hammering the GoMag API each minute,
and order-detail 500'd.

- database.ensure_oracle_pool(force): thread-safe (re)create of the pool, called
  at the start of every sync cycle → self-heals within one cycle once Oracle is
  back (incl. after an Oracle service restart). init_oracle_client made idempotent
  so re-init can't fall back to thin mode.
- database.oracle_status() exposed; main.py startup is non-fatal via ensure pool.
- run_sync ensures the pool before the GoMag download; on failure it records a
  clear run status instead of crashing and skips the wasted API calls.
- /api/sync/health reports oracle_ready/last_error; dashboard health pill shows
  "Oracle indisponibil" (top priority). Recovery via the existing Start Sync button.
- order_detail degrades gracefully (200 without CODMAT + notice) instead of 500.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/tests/test_sync_health_endpoint.py

@@ -32,6 +32,9 @@ client = TestClient(app)
 @pytest.fixture(autouse=True)
 async def _reset():
     database.init_sqlite()
+    # Simulate Oracle up for health tests (no real pool in unit env).
+    _orig_pool = database.pool
+    database.pool = object()
     db = await sqlite_service.get_sqlite()
     try:
         await db.execute("DELETE FROM sync_phase_failures")
@@ -40,6 +43,7 @@ async def _reset():
     finally:
         await db.close()
     yield
+    database.pool = _orig_pool
 
 
 async def _make_run(run_id: str, status: str = "completed", offset: int = 0,
@@ -108,3 +112,12 @@ async def test_health_one_phase_failure_still_warning_not_healthy():
     # 1 recent phase failure → is_healthy stays True (<=1 tolerance); healthy
     assert data["is_healthy"] is True
     assert data["recent_phase_failures"]["invoice_check"] == 1
+
+
+async def test_health_oracle_down_not_healthy():
+    await _make_run("ok-oracle", status="completed")
+    database.pool = None  # simulate Oracle pool not initialized
+    r = client.get("/api/sync/health")
+    data = r.json()
+    assert data["oracle_ready"] is False
+    assert data["is_healthy"] is False