[STORY] US-053: Teams app registration + meeting-transcript webhook

[carloshumbertoreyesortiz]

Story US-053

Parent epic: E-00 — DevOps AI Capture Layer
Effort: L (8 pts)
Impl guide: §00.5.1 capture-layer.md (Teams)
Depends on: US-052

User story

As a developer in a Teams meeting, I want the meeting transcript to flow into the platform automatically when the meeting ends, so that requirements discussed verbally become traceable capture records without me re-typing.

Acceptance criteria

• Telenor M365 admin has registered the Teams app with Microsoft Graph permissions: OnlineMeetingTranscript.Read.All, User.Read.All
• Webhook subscription created for transcript-ready events on opted-in meetings
• Handler normalizes the transcript to NormalizedIntake with source:'teams', source_ref set to the Graph meeting ID
• Privacy boundary: only meetings explicitly tagged with [agentic] in the subject line are captured (opt-in, never opt-out)
• Smoke test: a recorded test meeting produces a NormalizedIntake record within 90 seconds of meeting end

_Parent epic: #89