style(ui): float remaining table/card containers to design system

Repo-wide sweep for the same flat 1px-border "fake card" pattern
already fixed in Dashboard/Kanban/JobDetailsDialog/auth pages this
session -- AddJobModal, Attachments, CompaniesTable, Correspondence,
EditJobDialog, and the admin audit/system/users pages all had a table
container or content box using border+divider instead of the
floating-shadow treatment used everywhere else now.

Left AppShell.tsx/App.tsx alone -- their border:1px+divider instances
are icon-button and badge outlines, not card containers; that's a
different, correct use of the pattern.

job-tracker-ui/src/components/AddJobModal.tsx

@@ -374,7 +374,7 @@ export default function AddJobModal({ open, onClose, onCreated, initialUrl }: Pr
     label: string,
     helperText: string,
   ) => (
-    <Box sx={{ p: 1.5, borderRadius: 2, border: "1px solid", borderColor: "divider", backgroundColor: "background.paper" }}>
+    <Box sx={{ p: 1.5, borderRadius: 2, border: "none", boxShadow: "0px 1px 2px 0px rgba(15,23,42,0.04), 0px 8px 24px -12px rgba(15,23,42,0.12)", backgroundColor: "background.paper" }}>
       <Box sx={{ display: "flex", alignItems: "center", justifyContent: "space-between", gap: 1, flexWrap: "wrap" }}>
         <Box>
           <Typography sx={{ fontWeight: 800 }}>{label}</Typography>