custom ecb is dynamic table and not system table from now on

web/src/schema/mod.rs

@@ -1229,19 +1229,17 @@ pub(crate) const MAX_TABLE_NAME_LENGTH: usize = MAX_IDENTIFIER_LENGTH
     - "_fk".len()
     - crate::system_column::LONGEST_SYSTEM_COLUMN_NAME;
 
-/// The tables the server provisions for a profile itself. A profile gets these
-/// when it is created, so a new table may not claim one of their names.
+/// Tables whose structure the server owns and provisions when their capability is enabled.
 ///
 /// Written down here because the backend does not report them: they are
 /// constants of three server modules rather than anything the catalog carries.
 /// A name the server adds to that set is a name this list will not know about
 /// until it is added here as well.
-pub(crate) const RESERVED_TABLE_NAMES: [&str; 5] = [
+pub(crate) const RESERVED_TABLE_NAMES: [&str; 4] = [
     "general_ledger",
     "journal_lines",
     "quantity_ledger",
     LEDGER_ACCOUNTS_TABLE,
-    "custom_exchange_rates",
 ];
 
 /// The identifier rules, plus the two a table name alone is held to.