Add Microsoft Teams as notification provider

[KillianLarcher]

Context

Portabase supports multiple notification providers (Slack, Telegram, Discord, etc.) used to deliver system events such as backup status and agent connectivity.

Objective

Add support for Microsoft Teams as a new notification provider, enabling Portabase to send event-based notifications to a Teams channel.

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Technical Implementation

1. Create Microsoft Teams notification provider

Implement sendTeams in:
src/features/notifications/providers/teams.ts

2. Register provider in notification system

• Add sendTeams to provider handlers:
  src/features/notifications/providers/index.ts

• Extend provider type system by adding teams to ProviderKind:
  src/features/notifications/types.ts

3. Implement Teams configuration form (schema + UI)

• Create validation schema:
  src/components/wrappers/dashboard/admin/channels/channel/channel-form/providers/notifications/forms/teams.schema.ts

• Create UI form component:
  src/components/wrappers/dashboard/admin/channels/channel/channel-form/providers/notifications/forms/teams.form.tsx

4. Integrate Teams into UI provider system

• Update channel form schema:
  src/components/wrappers/dashboard/admin/channels/channel/channel-form/channel-form.schema.ts

• Update provider registry:
  src/components/wrappers/dashboard/admin/channels/helpers/notification.tsx
  Remove preview: true for Teams provider.

• Update form renderer:
  Add teams case in renderChannelForm in:
  src/components/wrappers/dashboard/admin/channels/helpers/common.tsx

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Validation Requirements (mandatory)

The Pull Request must include screenshots demonstrating:

• “Add Notification Channel” dialog showing Microsoft Teams as an available provider
• Microsoft Teams configuration form in create mode
• Microsoft Teams configuration form in edit modee)

First Good issue

This issue is suitable for first-time contributors familiar with TypeScript and React.