feat(deploy): SemVer 版本管理 + 自动化发版流水线

- deploy.yml: tag 触发（v*.*.*），四阶段调脚本（compile/test/release/deploy）
- manual.yml: workflow_dispatch 支持手动回滚，checkout 指定 tag
- scripts/ci/compile.sh: 构建 Go 二进制 + Flutter Web，打包 dist/
- scripts/ci/test.sh: go test + flutter analyze
- scripts/ci/release.sh: 解析 CHANGELOG.md → 更新 version.yaml → 创建 Forgejo Release
- scripts/ci/deploy.sh: 从 Release 下载产物（自动/手动均可）→ 部署到 EC2
- CHANGELOG.md: Keep a Changelog 格式，初始 v1.0.0 条目
- backend: GetRelease 改读 version.yaml，移除 ENV 变量依赖
- backend/config/version.yaml: 重置为 v1.0.0
- web/download.html: 动态拉取 /api/v1/public/release 展示版本号和更新内容

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/config/version.yaml

@@ -1,10 +1,10 @@
-version: "1.1.1"
-build_number: 2
+version: "1.0.0"
+build_number: 1
 force_update: false
-release_notes: "修复了离线模式问题，优化状态栏显示"
+release_notes: "初始版本发布，完成核心库存管理功能。"
 download_urls:
   macos: ""
   windows: ""
   ios: ""
   android: ""
-  web: ""
+  web: "https://jiu.51yanmei.com/app"