fix(config): add SETTING_METADATA for db pool and upload rate limit settings

Add missing SETTING_METADATA entries for db_pool_size, db_max_overflow,
db_pool_timeout, db_pool_recycle, upload_rate_limit_per_user, and
upload_rate_limit_window so the test_all_config_settings_have_metadata
test passes.

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/utils/settings_service.py

@@ -39,6 +39,50 @@ SETTING_METADATA = {
         "required": True,
         "restart_required": True,
     },
+    "db_pool_size": {
+        "category": "Core",
+        "description": (
+            "Number of persistent database connections kept in the pool per worker process. "
+            "Ignored for SQLite (which uses NullPool). Default: 10."
+        ),
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": True,
+    },
+    "db_max_overflow": {
+        "category": "Core",
+        "description": (
+            "Additional database connections allowed beyond db_pool_size under burst load. "
+            "Ignored for SQLite. Default: 20."
+        ),
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": True,
+    },
+    "db_pool_timeout": {
+        "category": "Core",
+        "description": (
+            "Seconds to wait for a database connection from the pool before raising a TimeoutError. "
+            "Ignored for SQLite. Default: 30."
+        ),
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": True,
+    },
+    "db_pool_recycle": {
+        "category": "Core",
+        "description": (
+            "Recycle (close and reopen) database connections after this many seconds "
+            "to avoid stale connections. Ignored for SQLite. Default: 1800."
+        ),
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": True,
+    },
     "workdir": {
         "category": "Core",
         "description": "Working directory for file storage and processing",
@@ -2525,6 +2569,26 @@ SETTING_METADATA = {
         "required": False,
         "restart_required": True,
     },
+    "upload_rate_limit_per_user": {
+        "category": "Security",
+        "description": (
+            "Maximum number of file uploads allowed per user within the sliding window. "
+            "The effective limit may be reduced dynamically when the system is under heavy load. "
+            "Set to 0 to disable per-user upload rate limiting. Default: 20."
+        ),
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "upload_rate_limit_window": {
+        "category": "Security",
+        "description": ("Sliding window size in seconds for per-user upload rate limiting. Default: 60."),
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
     # CORS
     "cors_enabled": {
         "category": "Security",