feat: GitHub Code Search als Agent-Tool + Dashboard-Badges

- UseGitHubSearch Property im AgentRecord (Default: false)
- DB-Migration: use_github_search Spalte in agents
- Checkbox im Agent-Formular (Standard: unchecked)
- Tool nur aktiv wenn Agent-Checkbox UND GitHubToken konfiguriert
- includeGitHubSearch Parameter durch StreamChat/AddToolsToPayload
- Dashboard-Badges: 🔮 Auto-Kontext + 🐙 GitHub Search

wwwroot/js/pages/agent-page.js

@@ -53,6 +53,7 @@ registerPage('agent', {
     const useUserInfoEl = document.getElementById('agentUseUserInfo');
     const useMemoryEl = document.getElementById('agentUseMemory');
     const useAutoContextEl = document.getElementById('agentUseAutoContext');
+    const useGitHubSearchEl = document.getElementById('agentUseGitHubSearch');
     const webSearchVersionEl = document.getElementById('agentWebSearchVersion');
     const avatarPreview = document.getElementById('avatarPreview');
     const saveBtn = document.getElementById('agentSaveBtn');
@@ -94,6 +95,7 @@ registerPage('agent', {
       useUserInfoEl.checked = agent.useUserInfo !== false;
       useMemoryEl.checked = agent.useMemory !== false;
       useAutoContextEl.checked = agent.useAutoContext !== false;
+      useGitHubSearchEl.checked = agent.useGitHubSearch || false;
       webSearchVersionEl.value = agent.webSearchVersion || '';
       isPublicEl.checked = agent.isPublic || false;
       deleteBtn.hidden = false;
@@ -136,6 +138,7 @@ registerPage('agent', {
         useUserInfo: useUserInfoEl.checked,
         useMemory: useMemoryEl.checked,
         useAutoContext: useAutoContextEl.checked,
+        useGitHubSearch: useGitHubSearchEl.checked,
         webSearchVersion: webSearchVersionEl.value,
         avatar: _agentAvatarEditor.getImage(),
         avatarScale: _agentAvatarEditor.getScale(),