feat: implement RAG-enabled chat hook and admin file upload component

src/components/admin/UploadZone.jsx

@@ -36,9 +36,16 @@ const UploadZone = ({ onUploadComplete }) => {
       })
       .catch((err) => {
         const isCancelled = err?.name === 'AbortError';
+        let errorMsg = err?.message || 'Unknown error';
+        if (err?.name === 'LLMTruncatedError') {
+          errorMsg = 'File is too large for the AI context window. Please split into smaller chunks.';
+        } else if (err?.name === 'LLMValidationError') {
+          errorMsg = 'AI output was malformed (not JSON). Please try again.';
+        }
+        
         setQueue((q) => q.map((item) =>
           item.id === next.id
-            ? { ...item, status: isCancelled ? 'cancelled' : 'failed', error: isCancelled ? null : err.message }
+            ? { ...item, status: isCancelled ? 'cancelled' : 'failed', error: isCancelled ? null : errorMsg }
             : item
         ));
       })

src/components/chat/useChat.js

@@ -193,13 +193,24 @@ export function useChat({ user, isAdmin }) {
     } catch (e) {
       console.error('[R42] chat error', e);
       setErrored(true);
-      const isKey = /api key/i.test(e?.message || '');
+      
+      let errorContent = STRINGS.errorGeneric;
+      const errorMsg = e?.message || '';
+      
+      if (e?.name === 'LLMTruncatedError') {
+        errorContent = 'Mijn circuits zijn overbelast (Token Limiet bereikt). Kun je je vraag korter of specifieker maken?';
+      } else if (e?.name === 'LLMValidationError') {
+        errorContent = 'Mijn antwoord was helaas beschadigd of incorrect geformatteerd. Kun je het nog eens proberen?';
+      } else if (/api key/i.test(errorMsg)) {
+        errorContent = STRINGS.errorNoKey;
+      }
+
       setMessages(prev => [
         ...prev,
         {
           id: `m_${Date.now()}_e`,
           role: 'error',
-          content: isKey ? STRINGS.errorNoKey : STRINGS.errorGeneric,
+          content: errorContent,
           ts: Date.now(),
         },
       ]);

src/lib/api.js

@@ -1,39 +0,0 @@
-/**
- * Back-compatibility shim for the legacy `anthropicApi` interface.
- *
- * All real work lives in `./llm.js`. Existing callers (extractionPipeline,
- * learningService, testService, KnowledgeGraph, useChat) keep working
- * unchanged; new code should import `callLLM` from `./llm.js` directly.
- */
-
-import { callLLM } from './llm';
-
-export const anthropicApi = {
-  async generateContent(systemPrompt, userMessage /*, maxRetries */) {
-    const { text } = await callLLM({
-      task: 'legacy.generateContent',
-      tier: 'standard',
-      system: systemPrompt,
-      user: userMessage,
-      maxTokens: 8192,
-      temperature: 0,
-    });
-    return text;
-  },
-
-  async chat(systemPrompt, messages, opts = {}) {
-    const r = await callLLM({
-      task: 'legacy.chat',
-      tier: 'standard',
-      system: systemPrompt,
-      messages,
-      tools: opts.tools,
-      maxTokens: 1024,
-      temperature: 0.3,
-    });
-    const content = [];
-    if (r.text) content.push({ type: 'text', text: r.text });
-    for (const tu of r.toolUses) content.push({ type: 'tool_use', name: tu.name, input: tu.input });
-    return { content, stop_reason: r.stopReason };
-  },
-};