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/app/main.py

@@ -7,7 +7,7 @@ import logging
 import os
 
 from .config import settings
-from .database import init_oracle, close_oracle, init_sqlite
+from .database import ensure_oracle_pool, close_oracle, init_sqlite
 
 # Configure logging with both stream and file handlers
 _log_level = getattr(logging, settings.LOG_LEVEL.upper(), logging.INFO)
@@ -35,12 +35,10 @@ async def lifespan(app: FastAPI):
     """Startup and shutdown events."""
     logger.info("Starting GoMag Import Manager...")
 
-    # Initialize Oracle pool
-    try:
-        init_oracle()
-    except Exception as e:
-        logger.error(f"Oracle init failed: {e}")
-        # Allow app to start even without Oracle for development
+    # Initialize Oracle pool (non-fatal: app still starts if Oracle is down;
+    # each sync cycle calls ensure_oracle_pool() and self-heals when it returns)
+    if not ensure_oracle_pool():
+        logger.error("Oracle pool not ready at startup — will retry on each sync cycle")
 
     # Initialize SQLite
     init_sqlite()