feat: v2.0 — maintenance module, AI analysis, station power fix

- Add full 检修维护中心 (6.4): 3-type work orders (消缺/巡检/抄表),
  asset management, warehouse, work plans, billing settlement
- Add AI智能分析 tab with LLM-powered diagnostics (StepFun + ZhipuAI)
- Add AI模型配置 settings page (provider, temperature, prompts)
- Fix station power accuracy: use API station total (station_power)
  instead of inverter-level computation — eliminates timing gaps
- Add 7 new DB models, 4 new API routers, 5 new frontend pages
- Migrations: 009 (maintenance expansion) + 010 (AI analysis)
- Version bump: 1.6.1 → 2.0.0

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

VERSIONS.json

@@ -1,9 +1,9 @@
 {
   "project": "zpark-ems",
-  "project_version": "1.6.1",
+  "project_version": "2.0.0",
   "customer": "Z-Park 中关村医疗器械园",
   "core_version": "1.4.0",
   "frontend_template_version": "1.4.0",
-  "last_updated": "2026-04-06",
-  "notes": "Fix devices.json protocol (http_api→sungrow_api) to enable Sungrow collectors"
+  "last_updated": "2026-04-12",
+  "notes": "v2.0: Maintenance module (6.4), AI analysis + model settings, station power accuracy fix"
 }