feat: 清理示例数据并统一空态体验

docs/plans/2026-03-30-remove-demo-study-seed-implementation.md

@@ -2,9 +2,9 @@
 
 > **For Claude:** REQUIRED SUB-SKILL: Use superpowers:executing-plans to implement this plan task-by-task.
 
-**Goal:** Stop development initialization from auto-creating any demo study or fee data.
+**Goal:** Stop development initialization from auto-creating any placeholder study or fee data.
 
-**Architecture:** Remove the application startup hook that seeds demo fee data, while keeping schema setup and protected admin initialization intact. Add a regression test that proves the lifespan startup no longer calls the demo seed helper.
+**Architecture:** Remove the application startup hook that seeds placeholder fee data, while keeping schema setup and protected admin initialization intact. Add a regression test that proves the lifespan startup no longer calls the old seed helper.
 
 **Tech Stack:** FastAPI, pytest, unittest.mock
 
@@ -19,18 +19,18 @@
 **Step 1: Write the failing test**
 
 ```python
-async def test_development_startup_does_not_seed_demo_fees():
+async def test_development_startup_does_not_seed_business_data():
     ...
 ```
 
 **Step 2: Run test to verify it fails**
 
 Run: `pytest backend/tests/test_app_startup.py -q`
-Expected: FAIL because startup still calls `seed_demo_fees`.
+Expected: FAIL because startup still calls the old seed helper.
 
 **Step 3: Write minimal implementation**
 
-Remove the `seed_demo_fees` import and startup call from `backend/app/main.py`.
+Remove the obsolete seed hook from `backend/app/main.py`.
 
 **Step 4: Run test to verify it passes**