feat(permissions) : add role-based UI guards and readonly mode for viewers

- Add usePermissions composable (isAdmin, canEdit, canView)
- Password-protected profile login with modal on profiles page
- Disable all form fields for ROLE_VIEWER across edit/create pages
- Show navigation buttons (Modifier/Consulter) for all roles, hide delete for viewers
- Add readonly prop to ModelTypeForm for category pages
- Disable modal fields (sites, constructeurs) for viewers
- Guard /admin routes in middleware

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

app/composables/useProfiles.ts

@@ -1,9 +1,13 @@
-import { useState, useRequestHeaders, useRuntimeConfig } from '#imports'
+import { useState, useRuntimeConfig } from '#imports'
 
 export interface Profile {
   id: string
   firstName: string
   lastName: string
+  email?: string | null
+  isActive?: boolean
+  hasPassword?: boolean
+  roles?: string[]
   [key: string]: unknown
 }
 
@@ -18,19 +22,12 @@ export function useProfiles() {
   const loadingProfiles = useState<boolean>('profiles:loading', () => false)
   const profilesLoaded = useState<boolean>('profiles:loaded', () => false)
 
-  const getSessionHeaders = (): Record<string, string> | undefined => {
-    if (!import.meta.server) { return undefined }
-    const headers = useRequestHeaders(['cookie'])
-    return headers?.cookie ? { cookie: headers.cookie } : undefined
-  }
-
   const fetchProfiles = async (): Promise<Profile[]> => {
     loadingProfiles.value = true
     try {
       profiles.value = await $fetch<Profile[]>(buildUrl('/session/profiles'), {
         method: 'GET',
         credentials: 'include',
-        headers: getSessionHeaders(),
       })
       profilesLoaded.value = true
     } catch (error) {
@@ -43,32 +40,10 @@ export function useProfiles() {
     return profiles.value
   }
 
-  const createProfile = async ({ firstName, lastName }: { firstName: string; lastName: string }): Promise<Profile> => {
-    const profile = await $fetch<Profile>(buildUrl('/session/profiles'), {
-      method: 'POST',
-      credentials: 'include',
-      body: { firstName, lastName },
-      headers: getSessionHeaders(),
-    })
-    await fetchProfiles()
-    return profile
-  }
-
-  const deleteProfile = async (profileId: string): Promise<void> => {
-    await $fetch(buildUrl(`/session/profiles/${profileId}`), {
-      method: 'DELETE',
-      credentials: 'include',
-      headers: getSessionHeaders(),
-    })
-    await fetchProfiles()
-  }
-
   return {
     profiles,
     loadingProfiles,
     profilesLoaded,
     fetchProfiles,
-    createProfile,
-    deleteProfile,
   }
 }