feat(tkeg, gateway): tkeg 대시보드 리디자인 + gateway 구매관리 네이밍 수정

- tkeg: MUI 기반 대시보드 전면 리디자인 (theme, 메트릭 카드, 프로젝트 Autocomplete, Quick Action, 관리자 섹션)
- gateway: tkpurchase 카드 "소모품 관리" → "구매관리"로 복원

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tkeg/web/src/theme.js

@@ -0,0 +1,42 @@
+import { createTheme } from '@mui/material/styles';
+
+const theme = createTheme({
+  palette: {
+    primary: { main: '#2563eb' },
+    success: { main: '#16a34a' },
+    warning: { main: '#d97706' },
+    background: {
+      default: '#f9fafb',
+      paper: '#ffffff',
+    },
+    divider: '#e5e7eb',
+    text: {
+      primary: '#111827',
+      secondary: '#6b7280',
+    },
+  },
+  shape: { borderRadius: 8 },
+  typography: {
+    fontFamily: '-apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif',
+    h4: { fontWeight: 700 },
+    h5: { fontWeight: 700 },
+    h6: { fontWeight: 600 },
+  },
+  components: {
+    MuiCard: {
+      styleOverrides: {
+        root: {
+          boxShadow: '0 1px 3px rgba(0,0,0,0.08)',
+          border: '1px solid #e5e7eb',
+        },
+      },
+    },
+    MuiButton: {
+      styleOverrides: {
+        root: { textTransform: 'none', fontWeight: 600 },
+      },
+    },
+  },
+});
+
+export default theme;