Add local YAML file import feature for subscription manager

[kitenium]

订阅管理器支持本地 YAML 文件导入

概述

在订阅管理器对话框中新增「本地文件导入」标签页，支持上传本地 Clash/Mihomo YAML 配置文件，自动解析并导入代理节点。此前用户只能通过订阅链接或分享链接导入节点，本次更新新增了基于本地文件的第三种导入方式。

新增功能

• 新增「本地文件导入」标签页：支持拖拽上传和点击选择文件
• 自动检测文件格式：Clash/Mihomo YAML（含 proxies 字段）、纯文本 URI 列表、Base64 编码的 URI 列表
• 导入后自动关联订阅配置：上传的节点会关联到一个自动创建的订阅配置（本地YAML导入），可在订阅配置管理中统一管理
• 支持格式：.yaml、.yml、.txt

改动详情

后端 (ss_node_subscribe.sh)

• subprof_create_local_import_profile() — 创建本地导入的订阅配置 dbus 记录，确保导入节点正确关联到订阅配置
• start_yaml_file_import()（action "5"）— 主导入入口：定位上传文件、校验大小、创建订阅配置、通过 sub-tool inspect 检测格式并解析，写入 dbus 时关联 _profile_id
• 支持三种格式：clash-yaml、uri-lines、base64-uri-lines

前端 (Module_shadowsocks.asp)

• 订阅管理器对话框中新增「本地文件导入」标签页
• 拖拽区域支持 ondragover/ondrop 事件（调用 preventDefault() 阻止浏览器默认下载行为）
• on_submgr_yaml_file_dropped() — 处理拖拽文件，校验扩展名，暂存文件
• on_submgr_yaml_file_selected() — 处理点击选择文件
• submit_subscription_yaml_from_manager() — 通过 FormData 上传文件至 /_upload，完成后触发导入 action "5"
• 导入完成后自动切换到订阅配置管理标签页，无需手动关闭再重新打开
• YAML 标签页下按钮文案改为「上传并解析节点」

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Add Local YAML File Import for Subscription Manager

Summary

Add a new "本地文件导入" (Local File Import) tab in the subscription manager dialog, allowing users to upload local Clash/Mihomo YAML configuration files and import proxy nodes directly. Previously, users could only import nodes via subscription URLs or share links — this adds a third entry point for local file-based imports.

What's New

• New "本地文件导入" tab in the subscription manager with drag-and-drop and click-to-browse file upload
• Auto-detects file format: Clash/Mihomo YAML (with proxies field), plain URI lines, or base64-encoded URI blocks
• Imports into a subscription profile: uploaded nodes are associated with a created profile record (本地YAML导入), so they appear in the profiles list and can be managed like regular subscriptions
• Supports formats: .yaml, .yml, .txt

Changes

Backend (ss_node_subscribe.sh)

• subprof_create_local_import_profile() — creates a subscription profile dbus record for local file imports so imported nodes are properly associated with a profile
• start_yaml_file_import() (action "5") — the main import entry point: locates the uploaded file, validates size, creates a profile, detects format via sub-tool inspect, parses accordingly, and writes nodes to dbus with _profile_id association
• Handles three format cases: clash-yaml, uri-lines, and base64-uri-lines

Frontend (Module_shadowsocks.asp)

• Added "本地文件导入" tab in the subscription manager dialog UI
• Drop zone with ondragover/ondrop handlers (calls preventDefault() to stop browser from downloading the file)
• on_submgr_yaml_file_dropped() — handles drag-and-drop file input, validates extension, stores file for upload
• on_submgr_yaml_file_selected() — handles click-to-browse file selection
• submit_subscription_yaml_from_manager() — uploads file via FormData to /_upload, then triggers import action "5"
• Auto-switches to the profiles tab after import completes so the user sees the updated profile list immediately
• Button relabeled to "上传并解析节点" when on the YAML tab