feat(tasks): 任务增加可选名称字段

tasks 表新增 name 列(空=未命名,前端回退到描述),端到端打通:
- DB: schema.sql 加列并补旧库 ALTER;tasks.go 的 Task/CreateOptions/CRUD;
  findings.go 分组与任务下拉带出 t.name
- 后端: TaskDTO、内存 Task、createTaskReq 透传 name
- 前端: 类型/API/mock 加 name;任务列表新增名称列与搜索、创建表单加名称输入;
  详情页与漏洞页标题回退 name || description

Claude-Session: https://claude.ai/code/session_019QXSCDmzimwnjntBNCgUD7

db/schema.sql

@@ -324,6 +324,7 @@ CREATE TABLE IF NOT EXISTS llm_profile_health (
 -- =====================================================================
 CREATE TABLE IF NOT EXISTS tasks (
     id             BIGSERIAL PRIMARY KEY,
+    name           TEXT NOT NULL DEFAULT '',
     description    TEXT NOT NULL,
     goal           TEXT NOT NULL,
     exploration_id BIGINT NOT NULL UNIQUE
@@ -367,6 +368,8 @@ ALTER TABLE tasks ADD COLUMN IF NOT EXISTS coverage_enabled BOOLEAN NOT NULL DEF
 -- exploration that already owns goals/history.
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS queued_at TIMESTAMPTZ;
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS queue_mode TEXT NOT NULL DEFAULT '';
+-- 可选的任务名称;补旧库。空串=未命名,前端展示时回退到描述。
+ALTER TABLE tasks ADD COLUMN IF NOT EXISTS name TEXT NOT NULL DEFAULT '';
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS active_llm_profile_id BIGINT REFERENCES llm_profiles(id) ON DELETE SET NULL;
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS llm_chain_revision BIGINT NOT NULL DEFAULT 0;