fix: web_search_tool_result als Raw-JSON speichern für History-Rebuild

Problem: API 400 'web_search tool use without corresponding
web_search_tool_result block' – weil web_search_tool_result nur als
Sources-Array gespeichert wurde und in BuildHistoryFromDb kein Handler
dafür existierte. Der server_tool_use-Block war in der History, aber
der zugehörige web_search_tool_result fehlte.

Backend (AnthropicService):
- 3 Speicher-Stellen (StreamChat, RunAgentChat, ChatNonStreaming):
  Raw-JSON statt ExtractWebSearchSources-Array speichern

Backend (ChatService):
- Neuer Handler für web_search_result in BuildHistoryFromDb:
  Raw-JSON als web_search_tool_result in assistant content einfügen
- Rückwärtskompatibilität: Alte Array-Einträge überspringen
- CleanOrphanedWebSearchBlocks(): Post-Processing entfernt
  orphaned server_tool_use mit name web_search (alte DB-Einträge)

Frontend (history.js, shared-page.js):
- _extractWebSearchSources(): Unterstützt altes Array-Format und
  neues Raw-JSON Format (content[].type === web_search_result)

wwwroot/js/history.js

@@ -1,3 +1,26 @@
+// ── Web Search Sources Extraction ──
+// Unterstützt zwei Formate:
+// - Alt: JSON-Array von {url, title} (nur Sources)
+// - Neu: Raw web_search_tool_result JSON (content[].type === 'web_search_result')
+function _extractWebSearchSources(content) {
+  try {
+    var parsed = JSON.parse(content || '[]');
+    // Altes Format: direktes Array von Sources
+    if (Array.isArray(parsed)) return parsed;
+    // Neues Format: Raw web_search_tool_result mit content-Array
+    if (parsed.content && Array.isArray(parsed.content)) {
+      var sources = [];
+      parsed.content.forEach(function(item) {
+        if (item.type === 'web_search_result' && item.url) {
+          sources.push({ url: item.url, title: item.title || '' });
+        }
+      });
+      return sources;
+    }
+    return [];
+  } catch(e) { return []; }
+}
+
 // ── Image Attachments Auto-Loading ──
 
 async function _autoLoadImageAttachments(messageId) {
@@ -246,8 +269,7 @@ function _renderMessagesIntoFragment(fragment, msgs, imageMessageIds, opts) {
         break;
       case 'web_search_result': {
         if (!isToolVisible('web_search')) continue;
-        var wsSources = [];
-        try { wsSources = JSON.parse(msg.content || '[]'); } catch(e) {}
+        var wsSources = _extractWebSearchSources(msg.content);
         if (wsSources.length === 0) continue;
         var wsDiv = document.createElement('div');
         wsDiv.className = 'tool-box' + (archived ? ' archived' : '');
@@ -350,8 +372,7 @@ function _renderReviewGroup(tagGroup, archived) {
     } else if (m.type === 'web_search_result') {
       if (!isToolVisible('web_search')) continue;
       flushText();
-      var wsSources = [];
-      try { wsSources = JSON.parse(m.content || '[]'); } catch(e) {}
+      var wsSources = _extractWebSearchSources(m.content);
       if (wsSources.length > 0) {
         var wsDiv = document.createElement('div');
         wsDiv.className = 'tool-box review-tool-box' + (archived ? ' archived' : '');

wwwroot/js/pages/shared-page.js

@@ -29,8 +29,7 @@ registerPage('shared', {
 
         // Web-Search-Results als Tool-Box mit Sources rendern
         if (msg.type === 'web_search_result') {
-          var wsSources = [];
-          try { wsSources = JSON.parse(c || '[]'); } catch(e) {}
+          var wsSources = _extractWebSearchSources(c);
           if (wsSources.length === 0) continue;
           const div = document.createElement('div');
           div.className = 'tool-box';