docs(ms-teams): promote "Enable the Teams channel" to its own step (EN+ZH)

[FelixLin6]

Why

Enabling the Microsoft Teams channel on the Azure Bot was buried as sub-item 5 of "Step 2: Configure the Bot and Note Credentials" — thematically misplaced (Step 2 is about credentials) and easy to skip. Skipping it is the cause of the "Invalid Bot" error when users try to chat, so it deserves to be unmissable.

What

• Promotes it to its own Step 3: Enable the Microsoft Teams Channel, with a "required and easy to miss" callout and the existing "Invalid Bot" Important note.
• Renumbers the subsequent Teams-deployment steps accordingly (EN: 3→…→12; ZH: 3→…→11).
• Updates the cross-references that point into the renumbered range:
  • channels/ms-teams.md: reactions setup "See Step 10" → Step 11 (EN).
  • zh/channels/ms-teams.md: deployment-guide reference 第8步 → 第9步 (preserves the original target through the renumber).

Scope

• Microsoft Teams entry only (no other channel touched), both EN and ZH guides + their two usage-doc cross-refs. 4 files.

FYI (pre-existing, not changed here)

The bumped ZH reference (zh/channels/ms-teams.md, "未配置 App Catalog ID。请参阅部署指南第9步") points at the Publish step, but App Catalog ID is actually obtained/entered in the Teams Developer Portal / Connect-in-Dashboard steps — a pre-existing mismatch. I only preserved its original target through the renumber rather than guess a re-target; worth correcting in the broader guide rework.

🤖 Generated with Claude Code

[Nanyan]

Clean restructure. Step numbering and cross-references are consistent across all 4 files (EN+ZH deployment guides + troubleshooting tables). The pre-existing ZH cross-ref mismatch (App Catalog ID → Publish step) is noted and reasonably out of scope.