diff --git a/backend/src/#repo.go# b/backend/src/#repo.go#
deleted file mode 100644
index 45c46ae..0000000
--- a/backend/src/#repo.go#
+++ /dev/null
@@ -1,17 +0,0 @@
-# Directory: internal/db/db.go
-
-# Directory: internal/db/repo.go
-
-# Directory: internal/glue/conversations.go
-
-# Directory: internal/glue/branches.go
-
-# Directory: internal/glue/completion.go
-
-# Directory: internal/glue/linearize.go
-
-# Directory: internal/http/router.go
-
-# Directory: internal/http/middleware.go
-
-# Directory: migrations/0001_init.sql
diff --git a/backend/src/.#repo.go b/backend/src/.#repo.go
deleted file mode 120000
index 61b330a..0000000
--- a/backend/src/.#repo.go
+++ /dev/null
@@ -1 +0,0 @@
-peisongxiao@PeisongXiao.4764:1760154185
\ No newline at end of file
diff --git a/backend/src/repo.go b/backend/src/repo.go
deleted file mode 100644
index b33ad96..0000000
--- a/backend/src/repo.go
+++ /dev/null
@@ -1,126 +0,0 @@
-# Directory: internal/db/db.go
-
-# Directory: internal/db/repo.go
-
-# Directory: internal/glue/conversations.go
-
-# Directory: internal/glue/branches.go
-
-# Directory: internal/glue/completion.go
-
-# Directory: internal/glue/linearize.go
-
-# Directory: internal/http/router.go
-
-# Directory: internal/http/middleware.go
-package http
-
-import "net/http"
-
-func withCommon(next http.Handler) http.Handler {
-	return http.TimeoutHandler(next, 60_000_000_000, "timeout") // 60s
-}
-
-# Directory: internal/http/handlers.go
-package http
-
-import (
-	"encoding/json"
-	"net/http"
-	"strconv"
-
-	"mind/internal/glue"
-)
-
-// POST /conversations  {"title":"demo","owner_id":1}
-// GET  /conversations?owner_id=1
-func (s *server) conversations(w http.ResponseWriter, r *http.Request) {
-	switch r.Method {
-	case http.MethodPost:
-		var in struct { Title string `json:"title"`; OwnerID int64 `json:"owner_id"` }
-		if err := json.NewDecoder(r.Body).Decode(&in); err != nil { writeJSON(w, 400, map[string]string{"error":"bad json"}); return }
-		id, err := s.glue.CreateConversation(r.Context(), in.OwnerID, in.Title)
-		if err != nil { writeJSON(w, 500, map[string]string{"error": err.Error()}); return }
-		writeJSON(w, 200, map[string]any{"id": id})
-	case http.MethodGet:
-		ownerStr := r.URL.Query().Get("owner_id")
-		owner, _ := strconv.ParseInt(ownerStr, 10, 64)
-		out, err := s.glue.ListConversations(r.Context(), owner)
-		if err != nil { writeJSON(w, 500, map[string]string{"error": err.Error()}); return }
-		writeJSON(w, 200, out)
-	default:
-		w.WriteHeader(405)
-	}
-}
-
-// POST /branches {conversation_id, name, head_node_id}
-func (s *server) branches(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodPost { w.WriteHeader(405); return }
-	var in glue.ForkReq
-	if err := json.NewDecoder(r.Body).Decode(&in); err != nil { writeJSON(w, 400, map[string]string{"error":"bad json"}); return }
-	b, err := s.glue.ForkBranch(r.Context(), in)
-	if err != nil { writeJSON(w, 500, map[string]string{"error": err.Error()}); return }
-	writeJSON(w, 200, b)
-}
-
-// POST /completion {conversation_id, branch, prompt}
-func (s *server) completion(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodPost { w.WriteHeader(405); return }
-	var in glue.CompletionReq
-	if err := json.NewDecoder(r.Body).Decode(&in); err != nil { writeJSON(w, 400, map[string]string{"error":"bad json"}); return }
-	resp, err := s.glue.AppendCompletion(r.Context(), in)
-	if err != nil { writeJSON(w, 500, map[string]string{"error": err.Error()}); return }
-	writeJSON(w, 200, resp)
-}
-
-// GET /linearize?conversation_id=..&branch=main
-func (s *server) linearize(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodGet { w.WriteHeader(405); return }
-	convID, _ := strconv.ParseInt(r.URL.Query().Get("conversation_id"), 10, 64)
-	branch := r.URL.Query().Get("branch")
-	out, err := s.glue.LinearizeByBranch(r.Context(), convID, branch)
-	if err != nil { writeJSON(w, 500, map[string]string{"error": err.Error()}); return }
-	writeJSON(w, 200, out)
-}
-
-# Directory: migrations/0001_init.sql
--- users (minimal for v0)
-CREATE TABLE IF NOT EXISTS users (
-  id           INTEGER PRIMARY KEY AUTOINCREMENT,
-  email        VARCHAR(255) UNIQUE,
-  pass_bcrypt  BLOB,
-  created_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP
-);
-
--- conversations
-CREATE TABLE IF NOT EXISTS conversations (
-  id           INTEGER PRIMARY KEY AUTOINCREMENT,
-  owner_id     INTEGER NOT NULL,
-  title        VARCHAR(255),
-  created_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP
-);
-
--- nodes
-CREATE TABLE IF NOT EXISTS nodes (
-  id              INTEGER PRIMARY KEY AUTOINCREMENT,
-  conversation_id INTEGER NOT NULL,
-  author_kind     ENUM('user','assistant') NOT NULL,
-  content         TEXT NOT NULL,
-  created_at      TIMESTAMP DEFAULT CURRENT_TIMESTAMP
-);
-
--- edges (DAG)
-CREATE TABLE IF NOT EXISTS edges (
-  parent_id    INTEGER NOT NULL,
-  child_id     INTEGER NOT NULL,
-  PRIMARY KEY(parent_id, child_id)
-);
-
--- branches (named pointers)
-CREATE TABLE IF NOT EXISTS branches (
-  id              INTEGER PRIMARY KEY AUTOINCREMENT,
-  conversation_id INTEGER NOT NULL,
-  name            VARCHAR(128) NOT NULL,
-  head_node_id    INTEGER NOT NULL,
-  UNIQUE (conversation_id, name)
-);