新增: F-260619-01 任务可关联灵感(tasks.idea_id 1对1 单向)

- df-storage V20 迁移:tasks 加 idea_id TEXT REFERENCES ideas(id)(填预留空位,
  幂等 column_exists 探测)+ V9_SQL 同步 + TaskRecord.idea_id + task_repo SQL/SELECT + 白名单
- AI 工具 create_task 加 idea_id 参数;update_task 经白名单自动支持
- IPC commands/task.rs CreateTaskInput 加 idea_id
- 前端 types TaskRecord/CreateTaskInput idea_id + TaskDetail.vue 关联灵感展示
  (router-link 友好 title 非裸 id)+ i18n
- 补 idea_id 字段:df-mcp tools / df-nodes 测试 helper
- 单向 1对1,Option 可空,复用 projects.idea_id 模式,老任务 None 兼容

自验: df-storage 47 passed(含 V20 2)+ workspace EXIT 0 + vue-tsc EXIT 0

src-tauri/src/commands/ai/tool_registry.rs

@@ -630,8 +630,8 @@ fn register_task_tools(registry: &mut AiToolRegistry, db: &Arc<Database>) {
         })},
     );
     registry.register(
-        "create_task", "在指定项目下创建新任务",
-        df_ai::ai_tools::object_schema(vec![("project_id", "string", true), ("title", "string", true), ("description", "string", false), ("priority", "integer", false)]),
+        "create_task", "在指定项目下创建新任务，可选传 idea_id 关联灵感(1对1 单向)",
+        df_ai::ai_tools::object_schema(vec![("project_id", "string", true), ("title", "string", true), ("description", "string", false), ("priority", "integer", false), ("idea_id", "string", false)]),
         RiskLevel::Medium,
         { let db = db.clone(); Box::new(move |args: serde_json::Value| {
             let db = db.clone();
@@ -647,6 +647,8 @@ fn register_task_tools(registry: &mut AiToolRegistry, db: &Arc<Database>) {
                     branch_name: None, assignee: None, workflow_def_id: None, base_branch: None,
                     review_rounds: 0,
                     output_json: None,
+                    // F-260619-01 可选关联灵感(空字符串/缺省视为不关联)
+                    idea_id: args.get("idea_id").and_then(|v| v.as_str()).filter(|s| !s.is_empty()).map(String::from),
                     created_at: now_millis(), updated_at: now_millis(),
                 };
                 let id = record.id.clone();