docs(getting-started): add EN Connect to Workspace tutorial

[Eriche985]

Adds a new English tutorial page Connect to OpenMax Workspace at docs/getting-started/connect-to-workspace.md (same level as channel-deployment), covering the full migration flow for existing Dashboard users:

• Part 1: Sign in and enter Workspace (steps 1-2)
• Part 2: Create your organization (step 3)
• Part 3: Connect your purchased AI employee via invite prompt (steps 4-6, incl. install confirmation and connected-greeting verification)
• Part 4: Manage Workspace — invite people, member admin, add more agents, agents page, connect chat channels, agent policy configuration, create group chats (steps 7-13)

Also:

• 22 new screenshots docs/public/ws-s*.png
• EN sidebar entry Connect to Workspace added in docs/.vitepress/config.mjs

Alt texts contain no double quotes (lesson from #184).

🤖 Generated with Claude Code

[tyler-0xffff]

内容核对通过：纯新增 docs/getting-started/connect-to-workspace.md（+147）+ 1 行 EN sidebar 配置，未改动任何现有页面。22 张 ws-s*.png 图片引用 22↔22 全匹配无断链/孤儿；22 个 标签均 6 引号结构完整（#184 直引号教训已规避）。LGTM ✅ 已开启 auto-merge，CI 全绿后自动 squash 合并。