fix: chatbot corpus onMounted + CSS auteurs lisibilite + remove /rag placeholder

- ChatbotPensees: deplace lecture localStorage dans onMounted (fix bug hydratation SSR/CSR, corpus 'both' garanti au render initial)
- CartePensees: opacity 1, stroke-width 2px, font-weight 600 (auteurs lisibles sur fond pastel)
- pages/rag.vue: supprime la page placeholder /rag (route disparait, Nuxt retourne 404)

components/ChatbotPensees.vue

@@ -213,18 +213,16 @@ const corpusCount = 18
 
 const corpus = ref<CorpusMode>('both')
 
-if (typeof window !== 'undefined') {
+onMounted(() => {
   const saved = window.localStorage.getItem(CORPUS_STORAGE_KEY) as CorpusMode | null
   if (saved && ['pensees', 'projets', 'both'].includes(saved)) {
     corpus.value = saved
   }
-}
+})
 
 function setCorpus(val: CorpusMode) {
   corpus.value = val
-  if (typeof window !== 'undefined') {
-    window.localStorage.setItem(CORPUS_STORAGE_KEY, val)
-  }
+  window.localStorage.setItem(CORPUS_STORAGE_KEY, val)
 }
 
 watch(open, (val) => {