step 10: plugins system (Lua + templates) + DokuWiki as optional plugin

Plugin Manager:
- Discover plugins from .verstak/plugins/<name>/plugin.json
- Enable/disable per plugin
- Template definitions (JSON) → pre-filled node trees
- SQL migrations from plugins
- Built-in templates loaded from internal/core/plugins/builtin/templates/

Lua Runtime:
- Stub (gopher-lua placeholder) — ready for real implementation
- When dep added: hooks (on_init, on_vault_open, on_node_create),
  sandbox (no io/os.execute), Plugin API

GUI:
- Template selector in create node modal
- POST /api/nodes/from-template creates tree from template
- Built-in "Клиент" template: Overview note + Документы/Переписка/Скриншоты

CLI:
- verstak plugin list/enable/disable/templates

DokuWiki Importer:
- Moved to contrib/plugins/importer-dokuwiki/ (optional plugin)
- plugin.json + migration + README

DokuWiki removed from MVP core — now an opt-in plugin.

Acceptance: go build ./... pass, go test ./... pass (all packages).

internal/gui/index.html.go

@@ -207,6 +207,8 @@ input[type=checkbox]{width:auto!important;margin-right:6px;display:inline}
   <select id="mn-type"><option value="case">◇ Дело</option><option value="folder">▸ Папка</option><option value="space">◎ Пространство</option><option value="recipe">◈ Рецепт</option></select>
   <label for="mn-title">Название</label><input id="mn-title" placeholder="Название...">
   <label for="mn-parent">Родитель (опционально)</label><input id="mn-parent" placeholder="Имя папки или оставьте пустым">
+  <label>Шаблон</label>
+  <select id="mn-tmpl"><option value="">— без шаблона —</option></select>
   <div class="ma"><button class="btn" onclick="closeM('m-node')">Отмена</button><button class="btn primary" onclick="submitNode()">Создать</button></div></div>
 </div>
 <div class="mo" id="m-note">
@@ -674,7 +676,23 @@ async function submitWLEntry(nodeId){
 /* ════════════════════════════════════════════
    MODALS
    ════════════════════════════════════════════ */
-function openM(id){G(id).classList.add('on');setTimeout(()=>{const i=G(id).querySelector('input,textarea');if(i)i.focus()},60)}
+function openM(id){
+  G(id).classList.add('on');
+  setTimeout(()=>{const i=G(id).querySelector('input,textarea');if(i)i.focus()},60);
+  if(id==='m-node')loadTemplates();
+}
+async function loadTemplates(){
+  const sel=document.getElementById('mn-tmpl');
+  if(!sel)return;
+  try{
+    const tmpls=await api('/api/templates');
+    let h='<option value="">— без шаблона —</option>';
+    for(const t of tmpls){
+      h+='<option value="'+esc(t.name)+'">'+esc(t.name)+' ['+esc(t.plugin)+']</option>';
+    }
+    sel.innerHTML=h;
+  }catch(e){}
+}
 function closeM(id){G(id).classList.remove('on');G(id).querySelectorAll('input,textarea').forEach(e=>e.value='')}
 function doAdd(kind){
   closeAddMenu();
@@ -720,6 +738,7 @@ document.addEventListener('click',()=>closeAddMenu());
 
 async function submitNode(){
   const t=G('mn-type').value,title=G('mn-title').value.trim(),parentName=G('mn-parent').value.trim();
+  const tmpl=G('mn-tmpl').value;
   if(!title)return;
   let parentId='', section='';
   if(parentName){
@@ -732,7 +751,12 @@ async function submitNode(){
     section=sel.section;
   }
   try{
-    const n=await api('/api/nodes',{method:'POST',body:JSON.stringify({parent_id:parentId,type:t,title,section})});
+    let n;
+    if(tmpl){
+      n=await api('/api/nodes/from-template',{method:'POST',body:JSON.stringify({parent_id:parentId,type:t,title,section,template:tmpl})});
+    }else{
+      n=await api('/api/nodes',{method:'POST',body:JSON.stringify({parent_id:parentId,type:t,title,section})});
+    }
     closeM('m-node');
     const qs = section||'';
     const items=await api('/api/nodes?section='+encodeURIComponent(qs));

internal/gui/server.go

@@ -13,6 +13,7 @@ import (
 	"verstak/internal/core/files"
 	"verstak/internal/core/notes"
 	"verstak/internal/core/nodes"
+	"verstak/internal/core/plugins"
 	"verstak/internal/core/search"
 	"verstak/internal/core/storage"
 	"verstak/internal/core/worklog"
@@ -28,6 +29,7 @@ type Server struct {
 	actions   *actions.Service
 	worklog   *worklog.Service
 	search    *search.Service
+	plugins   *plugins.Manager
 	srv       *http.Server
 	listener  net.Listener
 	port      int
@@ -41,10 +43,12 @@ func NewServer(db *storage.DB, vaultRoot string) *Server {
 	actionSvc := actions.NewService(db)
 	workSvc := worklog.NewService(db)
 	srchSvc := search.NewService(db)
+	pluginMgr := plugins.NewManager(vaultRoot)
+	pluginMgr.Discover()
 	return &Server{
 		db: db, vaultRoot: vaultRoot,
 		nodes: nodeRepo, files: fileSvc, notes: noteSvc, actions: actionSvc,
-		worklog: workSvc, search: srchSvc,
+		worklog: workSvc, search: srchSvc, plugins: pluginMgr,
 	}
 }
 
@@ -52,11 +56,13 @@ func NewServer(db *storage.DB, vaultRoot string) *Server {
 func (s *Server) Start() (string, error) {
 	mux := http.NewServeMux()
 	mux.HandleFunc("/api/nodes", s.handleNodes)
+	mux.HandleFunc("/api/nodes/from-template", s.handleNodeFromTemplate)
 	mux.HandleFunc("/api/nodes/", s.handleNodeDetail)
 	mux.HandleFunc("/api/notes/", s.handleNotes)
 	mux.HandleFunc("/api/files/", s.handleFiles)
 	mux.HandleFunc("/api/actions/", s.handleActions)
 	mux.HandleFunc("/api/worklog/", s.handleWorklog)
+	mux.HandleFunc("/api/templates", s.handleTemplates)
 	mux.HandleFunc("/api/search", s.handleSearch)
 	mux.HandleFunc("/", s.handleStatic)
 
@@ -151,6 +157,65 @@ func (s *Server) handleNodes(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+// POST /api/nodes/from-template — create node tree from a template.
+func (s *Server) handleNodeFromTemplate(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		jsonErr(w, 405, "method not allowed")
+		return
+	}
+	var req struct {
+		ParentID string `json:"parent_id"`
+		Type     string `json:"type"`
+		Title    string `json:"title"`
+		Section  string `json:"section"`
+		Template string `json:"template"`
+	}
+	json.NewDecoder(r.Body).Decode(&req)
+
+	// Find the template.
+	var tmpl *plugins.TemplateDefinition
+	for _, t := range s.plugins.Templates() {
+		if t.Name == req.Template {
+			tmpl = &t
+			break
+		}
+	}
+	if tmpl == nil {
+		jsonErr(w, 404, "template not found")
+		return
+	}
+
+	// Create root node.
+	root, err := s.nodes.Create(req.ParentID, tmpl.RootType, req.Title, req.Section)
+	if err != nil {
+		jsonErr(w, 500, err.Error())
+		return
+	}
+
+	// Create children recursively.
+	var createTree func(parentID string, nodes []plugins.TreeNode) error
+	createTree = func(parentID string, nodes []plugins.TreeNode) error {
+		for _, tn := range nodes {
+			child, err := s.nodes.Create(parentID, tn.Type, tn.Title, "")
+			if err != nil {
+				return err
+			}
+			if len(tn.Children) > 0 {
+				if err := createTree(child.ID, tn.Children); err != nil {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	if err := createTree(root.ID, tmpl.Tree); err != nil {
+		jsonErr(w, 500, err.Error())
+		return
+	}
+
+	jsonOK(w, root)
+}
+
 // GET/PUT/DELETE /api/nodes/{id}
 func (s *Server) handleNodeDetail(w http.ResponseWriter, r *http.Request) {
 	id := strings.TrimPrefix(r.URL.Path, "/api/nodes/")
@@ -386,3 +451,12 @@ func (s *Server) handleSearch(w http.ResponseWriter, r *http.Request) {
 	}
 	jsonOK(w, results)
 }
+
+// GET /api/templates — list all templates from active plugins.
+func (s *Server) handleTemplates(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		jsonErr(w, 405, "method not allowed")
+		return
+	}
+	jsonOK(w, s.plugins.Templates())
+}