merge: upgrade to upstream v0.50.95 + keep custom additions

Upstream v0.50.95 features merged (Russian localization, slash commands,
mic toggle fix, gateway sync fix, KaTeX/Prism.js, etc.)

Custom additions preserved:
- Tier-2 agent switching commands in commands.js
- MC panel in index.html + MC CSS
- _resolve_cli_toolsets() in config.py
- Custom routes.py, server.py, boot.js, i18n.js, messages.js, workspace.js

Files with conflict resolution (took upstream, custom code in other files):
- CHANGELOG.md, config.py, commands.js, index.html, panels.js, style.css, ui.js

static/workspace.js

@@ -200,6 +200,7 @@ async function openFile(path){
   $('previewPathText').textContent=path;
   $('previewArea').classList.add('visible');
   $('fileTree').style.display='none';
+  const wsSearch=$('wsSearchWrap');if(wsSearch)wsSearch.style.display='none';
 
   _previewCurrentPath = path;
   renderFileBreadcrumb(path);
@@ -229,7 +230,27 @@ async function openFile(path){
         return;
       }
       showPreview('code');
-      $('previewCode').textContent=data.content;
+      // Apply syntax highlighting based on file extension
+      const content = data.content || '';
+      if(['yml','yaml'].includes(ext)){
+        $('previewCode').className='preview-code hl-yaml';
+        if(typeof highlightYAML==='function'){
+          $('previewCode').innerHTML=highlightYAML(content);
+        }else{
+          $('previewCode').innerHTML=_highlightWithLineNumbers(content);
+        }
+      }else if(ext==='json'){
+        $('previewCode').className='preview-code hl-json';
+        $('previewCode').innerHTML=_highlightJSON(content);
+      }else if(['py','js','ts','sh','bash','zsh','rb','go','rs','java','c','cpp','h','css','scss','html','xml','sql','r','lua','pl','php','swift','kt','dart'].includes(ext)){
+        $('previewCode').className='preview-code';
+        $('previewCode').textContent=content;
+        requestAnimationFrame(()=>{if(typeof highlightCode==='function')highlightCode();});
+      }else{
+        // txt, toml, cfg, ini, conf, env, log, etc — readable with line numbers
+        $('previewCode').className='preview-code hl-text';
+        $('previewCode').innerHTML=_highlightWithLineNumbers(content);
+      }
     }catch(e){
       // If it's a 400/too-large error, offer download instead
       downloadFile(path);
@@ -287,3 +308,131 @@ function renderFileBreadcrumb(filePath) {
     bar.appendChild(seg);
   }
 }
+
+// ── Syntax highlighting helpers for file preview ──
+function _escHtml(s){return s.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;').replace(/"/g,'&quot;');}
+
+function _highlightWithLineNumbers(text){
+  return text.split('\n').map(line=>'<span class="code-line">'+_escHtml(line)+'</span>').join('\n');
+}
+
+function _highlightJSON(text){
+  try{
+    const pretty=JSON.stringify(JSON.parse(text),null,2);
+    return pretty.split('\n').map(raw=>{
+      let line=_escHtml(raw);
+      // Highlight keys
+      line=line.replace(/^(\s*)(&quot;)([\w\s.\/\-_@:]+)(&quot;)(\s*:)/,'$1<span class="hl-key">$2$3$4</span><span class="hl-value">$5</span>');
+      // Highlight string values (after colon)
+      line=line.replace(/(:\s*)(&quot;[^&]*?&quot;)/g,'$1<span class="hl-string">$2</span>');
+      // Highlight numbers
+      line=line.replace(/:\s*(\d+\.?\d*)/g,': <span class="hl-number">$1</span>');
+      // Highlight booleans / null
+      line=line.replace(/:\s*(true|false|null)/g,': <span class="hl-bool">$1</span>');
+      return '<span class="code-line">'+line+'</span>';
+    }).join('\n');
+  }catch(e){
+    return _highlightWithLineNumbers(text);
+  }
+}
+
+// ── Workspace file search (server-side recursive) ──
+let _wsSearchTimer=null;
+function filterWsFiles(){
+  // Debounce: wait 300ms after last keystroke
+  clearTimeout(_wsSearchTimer);
+  _wsSearchTimer=setTimeout(_doWsSearch,300);
+}
+async function _doWsSearch(){
+  const input=$('wsSearchInput');
+  const clearBtn=$('wsSearchClear');
+  const tree=$('fileTree');
+  if(!input||!tree)return;
+  const query=input.value.trim().toLowerCase();
+  if(clearBtn)clearBtn.classList.toggle('visible',query.length>0);
+  // Remove any stale "no results" message
+  const oldNoRes=tree.querySelector('.ws-no-results');
+  if(oldNoRes)oldNoRes.remove();
+  // If empty query, restore original file tree
+  if(!query){
+    if(typeof renderFileTree==='function')renderFileTree();
+    return;
+  }
+  // Not searchable without a workspace
+  if(!S.session||!S.session.workspace)return;
+  // Show loading indicator
+  tree.innerHTML='<div class="ws-no-results" style="opacity:.5">Suche...</div>';
+  try{
+    // Ask server to search recursively
+    const data=await api(`/api/list?session_id=${encodeURIComponent(S.session.session_id)}&path=.&search=${encodeURIComponent(query)}`);
+    const results=data.entries||[];
+    if(!results.length){
+      tree.innerHTML='<div class="ws-no-results">Keine Dateien gefunden</div>';
+      return;
+    }
+    // Render flat result list with path info
+    tree.innerHTML='';
+    for(const item of results){
+      const el=document.createElement('div');
+      el.className='file-item';
+      el.style.paddingLeft='10px';
+      const iconEl=document.createElement('span');
+      iconEl.className='file-icon';
+      iconEl.innerHTML=fileIcon(item.name,item.type);
+      el.appendChild(iconEl);
+      const nameEl=document.createElement('span');
+      nameEl.className='file-name';
+      nameEl.textContent=item.name;
+      el.appendChild(nameEl);
+      // Show relative path as hint
+      if(item.path){
+        const pathEl=document.createElement('span');
+        pathEl.className='file-size';
+        pathEl.style.opacity='.4';
+        const dir=item.path.substring(0,item.path.lastIndexOf('/'));
+        pathEl.textContent=dir||'.';
+        el.appendChild(pathEl);
+      }
+      if(item.type==='dir'){
+        el.onclick=()=>{clearWsSearch();loadDir(item.path);};
+      }else{
+        el.onclick=()=>openFile(item.path);
+      }
+      tree.appendChild(el);
+    }
+  }catch(e){
+    // Fallback: client-side filter on currently visible items
+    tree.innerHTML='';
+    const allItems=S.entries||[];
+    const matches=allItems.filter(it=>it.name.toLowerCase().includes(query));
+    if(!matches.length){
+      tree.innerHTML='<div class="ws-no-results">Keine Dateien gefunden</div>';
+    }else{
+      for(const item of matches){
+        const el=document.createElement('div');
+        el.className='file-item';el.style.paddingLeft='10px';
+        el.innerHTML='<span class="file-icon">'+fileIcon(item.name,item.type)+'</span><span class="file-name">'+item.name+'</span>';
+        el.onclick=item.type==='dir'?()=>{clearWsSearch();loadDir(item.path);}:()=>openFile(item.path);
+        tree.appendChild(el);
+      }
+    }
+  }
+}
+
+// Toggle workspace search visibility
+function toggleWsSearch(){
+  const wrap=$('wsSearchWrap');
+  if(!wrap)return;
+  // Show/hide the search bar
+  wrap.style.display=wrap.style.display==='none'?'flex':'none';
+  // Focus input when showing
+  setTimeout(()=>{if(wrap.style.display!=='none'){const inp=$('wsSearchInput');if(inp)inp.focus();}},50);
+}
+
+function clearWsSearch(){
+  const input=$('wsSearchInput');
+  if(input)input.value='';
+  const clearBtn=$('wsSearchClear');
+  if(clearBtn)clearBtn.classList.remove('visible');
+  if(typeof renderFileTree==='function')renderFileTree();
+}