Merge all role-dispatcher pages into single files; add FileBrowser with file-type icons

- DashboardPage, Projects, RequestsPage, ProjectDetailPage, RequestDetail: each now handles team/external/client in one file via role flags — removed 10 old role-specific sub-files
- Layout: client Company nav link goes directly to /company/:id when user has a single company
- FileBrowser: replace emoji icons with colored extension-text badges (square); folder icon stays 📁; Adobe/Figma/design-tool colors for design files
- CompaniesPage: merged team Companies + client company routing (single-company redirect, multi-company list)
- FileSharing: integrated FileBrowser component
- Removed: seafile API + lib, old ServerStatus, TaskDetail, role-split page files

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

src/context/AuthContext.jsx

@@ -12,20 +12,24 @@ export function AuthProvider({ children }) {
 
   const fetchAndCacheProfile = async (authUser, attempt = 0) => {
     try {
-      const { data, error } = await Promise.race([
-        supabase
-          .from('profiles')
-          .select('*, company:companies(id, name, phone, address)')
-          .eq('id', authUser.id)
-          .single(),
+      const [profileResult, membershipsResult] = await Promise.race([
+        Promise.all([
+          supabase
+            .from('profiles')
+            .select('*, company:companies(id, name, phone, address)')
+            .eq('id', authUser.id)
+            .single(),
+          supabase
+            .from('company_members')
+            .select('company:companies(id, name, phone, address)')
+            .eq('profile_id', authUser.id),
+        ]),
         new Promise((_, reject) => setTimeout(() => reject(new Error('Profile fetch timeout')), 8000)),
       ]);
+
+      const { data, error } = profileResult;
       if (data) {
-        const { data: memberships } = await supabase
-          .from('company_members')
-          .select('company:companies(id, name, phone, address)')
-          .eq('profile_id', authUser.id);
-        const companies = (memberships || [])
+        const companies = ((membershipsResult.data || []))
           .map(membership => membership.company)
           .filter(Boolean);
         if (data.role === 'client' && data.company && !companies.some(company => company.id === data.company.id)) {