[Space Lua] Load scripts without priority last during reload

The new null-aware ordering in `orderByCompare` changed the default
placement of undefined values for descending sorts to `nulls first` (SQL
standard). This caused Space Lua scripts without a `-- priority:`
comment to load before the `Std` library scripts and breaking the boot
sequence for user scripts ran before `schema`, `config`, `widget` and
other core definitions were available.

Add explicit `nulls: "last"` to the reload query so scripts without
priority always load last, matching the documented behavior.

Signed-off-by: Matouš Jan Fialka <mjf@mjf.cz>

client/space_lua.ts

@@ -33,6 +33,7 @@ export class SpaceLuaEnvironment {
         orderBy: [{
           expr: parseExpressionString("script.priority"),
           desc: true,
+          nulls: "last",
         }],
       } as LuaCollectionQuery,
     );