feat: Refactor service management scripts to use a unified dev script

- Added package.json to manage development scripts.
- Updated restart-services.ps1 to call the new dev script for starting services.
- Refactored start-admin.ps1, start-backend.ps1, start-frontend.ps1, and start-mcp.ps1 to utilize the dev script for starting respective services.
- Enhanced stop-services.ps1 to improve process termination logic by matching command patterns.

frontend/src/layouts/BaseLayout.astro

@@ -121,7 +121,7 @@ const i18nPayload = JSON.stringify({ locale, messages });
       }
 
       @media (prefers-color-scheme: dark) {
-        :root:not(.light) {
+        :root:not(.light):not(.dark) {
           --primary: #00ff9d;
           --primary-rgb: 0 255 157;
           --primary-light: #00ff9d33;
@@ -193,12 +193,84 @@ const i18nPayload = JSON.stringify({ locale, messages });
 
     <script is:inline>
       (function() {
-        const theme = localStorage.getItem('theme');
-        const systemDark = window.matchMedia('(prefers-color-scheme: dark)').matches;
-        if (theme === 'dark' || (!theme && systemDark)) {
-          document.documentElement.classList.add('dark');
-        } else if (theme === 'light') {
-          document.documentElement.classList.add('light');
+        const STORAGE_KEY = 'theme';
+        const VALID_THEMES = new Set(['light', 'dark', 'system']);
+        const root = document.documentElement;
+        const mediaQuery = window.matchMedia('(prefers-color-scheme: dark)');
+
+        function readThemeMode() {
+          try {
+            const savedMode = localStorage.getItem(STORAGE_KEY);
+            return VALID_THEMES.has(savedMode) ? savedMode : 'system';
+          } catch {
+            return 'system';
+          }
+        }
+
+        function resolveTheme(mode) {
+          return mode === 'dark' || (mode === 'system' && mediaQuery.matches) ? 'dark' : 'light';
+        }
+
+        function applyTheme(mode, options = {}) {
+          const { persist = false, notify = true } = options;
+          const safeMode = VALID_THEMES.has(mode) ? mode : 'system';
+          const resolvedTheme = resolveTheme(safeMode);
+
+          root.dataset.themeMode = safeMode;
+          root.dataset.themeResolved = resolvedTheme;
+          root.classList.toggle('dark', resolvedTheme === 'dark');
+          root.classList.toggle('light', resolvedTheme === 'light');
+
+          if (persist) {
+            try {
+              localStorage.setItem(STORAGE_KEY, safeMode);
+            } catch {
+              // Ignore storage write failures and keep the UI responsive.
+            }
+          }
+
+          if (notify) {
+            window.dispatchEvent(
+              new CustomEvent('termi:theme-change', {
+                detail: { mode: safeMode, resolved: resolvedTheme },
+              })
+            );
+          }
+
+          return { mode: safeMode, resolved: resolvedTheme };
+        }
+
+        function syncThemeFromStorage(notify = false) {
+          return applyTheme(readThemeMode(), { notify });
+        }
+
+        window.__termiTheme = {
+          getMode: readThemeMode,
+          resolveTheme,
+          applyTheme(mode) {
+            return applyTheme(mode, { persist: true, notify: true });
+          },
+          syncTheme() {
+            return syncThemeFromStorage(true);
+          },
+        };
+
+        syncThemeFromStorage(false);
+
+        if (!window.__termiThemeMediaBound) {
+          const handleSystemThemeChange = () => {
+            if (readThemeMode() === 'system') {
+              syncThemeFromStorage(true);
+            }
+          };
+
+          if (typeof mediaQuery.addEventListener === 'function') {
+            mediaQuery.addEventListener('change', handleSystemThemeChange);
+          } else {
+            mediaQuery.onchange = handleSystemThemeChange;
+          }
+
+          window.__termiThemeMediaBound = true;
         }
       })();
     </script>