fix(ui): unify icon badges — solid tile + white glyph via shared helper

The labelled icon-badge tiles were inconsistent: some used a same-hue
light tile + colored glyph (e.g. the Settings 2FA row: success.light tile
+ success.main glyph — low contrast, the reported "badly visible" icon),
and the solid-tile ones used the bright .main fill in dark mode without
darkening, so a white glyph on bright green/amber was low-contrast too
(DashProfile's success badge was ~1.9:1).

Add a single `iconBadgeSx(color)` helper (theme.ts): solid `<color>.main`
fill + white glyph, darkened in dark mode (FILLED_DARK_BG) so white stays
legible; `default` = neutral grey. Applied to every badge so they can't
drift: StatCard, DashActivityFeed, DashProfile (2FA badge), Dashboard
(2FA banner icon), AttendanceHistory (month tile), and the Settings 2FA
row tile (now solid green when required / grey when optional + white lock,
instead of the low-contrast light-green tile). Also switched DashProfile's
backup-codes warning callout from warning.light to a subtle warning wash
so its amber text stays readable in dark mode.

tsc -b --noEmit, npm run build, vitest 152/152 all clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/admin/pages/AttendanceHistory.tsx

@@ -5,6 +5,7 @@ import Typography from "@mui/material/Typography";
 import { useAuth } from "../context/AuthContext";
 import Forbidden from "../components/Forbidden";
 import { companySettingsOptions } from "../lib/queries/settings";
+import { iconBadgeSx } from "../theme";
 import {
   attendanceHistoryOptions,
   type AttendanceRecord,
@@ -533,17 +534,18 @@ export default function AttendanceHistory() {
             }}
           >
             <Box
-              sx={{
-                display: "flex",
-                alignItems: "center",
-                justifyContent: "center",
-                width: 44,
-                height: 44,
-                borderRadius: 2,
-                bgcolor: "info.main",
-                color: "#fff",
-                flexShrink: 0,
-              }}
+              sx={[
+                {
+                  display: "flex",
+                  alignItems: "center",
+                  justifyContent: "center",
+                  width: 44,
+                  height: 44,
+                  borderRadius: 2,
+                  flexShrink: 0,
+                },
+                iconBadgeSx("info"),
+              ]}
             >
               <svg
                 width="24"