feat(api): A3 backend skeleton with FastAPI + SQLModel

- 3 tables: Meeting / TranscriptSegment / Summary (with state machine)
- Routes: /api/upload-url + /api/upload-complete + meetings CRUD
- MinIO presigned PUT for direct browser upload
- BackgroundTasks state-machine stub for A5 to flesh out
- SQLite for local dev, PostgreSQL+asyncpg for prod
- CORS configured for frontend on 4490

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/routers/meetings.py

@@ -0,0 +1,114 @@
+import uuid
+from fastapi import APIRouter, BackgroundTasks, Depends, HTTPException
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlmodel import select
+
+from ..db import get_session
+from ..models import Meeting, MeetingStatus, TranscriptSegment, Summary
+from ..schemas import (
+    MeetingRead,
+    UploadCompleteRequest,
+    UploadUrlRequest,
+    UploadUrlResponse,
+)
+from ..services.storage import presign_put
+from ..services.transcribe import process_meeting
+
+router = APIRouter(prefix="/api", tags=["meetings"])
+
+
+@router.post("/upload-url", response_model=UploadUrlResponse)
+async def request_upload_url(
+    body: UploadUrlRequest, session: AsyncSession = Depends(get_session)
+):
+    object_key = f"audio/{uuid.uuid4().hex}-{body.filename}"
+
+    meeting = Meeting(
+        title=body.title or body.filename,
+        participants=body.participants,
+        object_key=object_key,
+        status=MeetingStatus.uploading,
+    )
+    session.add(meeting)
+    await session.commit()
+    await session.refresh(meeting)
+
+    upload_url = presign_put(object_key, body.content_type)
+    return UploadUrlResponse(
+        meeting_id=meeting.id,
+        upload_url=upload_url,
+        object_key=object_key,
+    )
+
+
+@router.post("/upload-complete")
+async def upload_complete(
+    body: UploadCompleteRequest,
+    background: BackgroundTasks,
+    session: AsyncSession = Depends(get_session),
+):
+    meeting = await session.get(Meeting, body.meeting_id)
+    if not meeting:
+        raise HTTPException(404, "meeting not found")
+
+    meeting.file_size = body.file_size
+    meeting.status = MeetingStatus.uploaded
+    await session.commit()
+
+    background.add_task(process_meeting, meeting.id)
+    return {"ok": True, "meeting_id": meeting.id}
+
+
+@router.get("/meetings", response_model=list[MeetingRead])
+async def list_meetings(session: AsyncSession = Depends(get_session)):
+    result = await session.execute(select(Meeting).order_by(Meeting.created_at.desc()))
+    return result.scalars().all()
+
+
+@router.get("/meetings/{meeting_id}", response_model=MeetingRead)
+async def get_meeting(meeting_id: int, session: AsyncSession = Depends(get_session)):
+    meeting = await session.get(Meeting, meeting_id)
+    if not meeting:
+        raise HTTPException(404, "meeting not found")
+    return meeting
+
+
+@router.get("/meetings/{meeting_id}/transcript")
+async def get_transcript(meeting_id: int, session: AsyncSession = Depends(get_session)):
+    result = await session.execute(
+        select(TranscriptSegment)
+        .where(TranscriptSegment.meeting_id == meeting_id)
+        .order_by(TranscriptSegment.start)
+    )
+    segments = result.scalars().all()
+    return [
+        {"start": s.start, "end": s.end, "speaker": s.speaker, "text": s.text}
+        for s in segments
+    ]
+
+
+@router.get("/meetings/{meeting_id}/summary")
+async def get_summary(meeting_id: int, session: AsyncSession = Depends(get_session)):
+    result = await session.execute(
+        select(Summary).where(Summary.meeting_id == meeting_id)
+    )
+    summary = result.scalar_one_or_none()
+    if not summary:
+        return None
+    return {
+        "key_points": summary.key_points,
+        "todos": summary.todos,
+        "decisions": summary.decisions,
+        "keywords": summary.keywords,
+        "preview": summary.preview,
+    }
+
+
+@router.delete("/meetings/{meeting_id}")
+async def delete_meeting(meeting_id: int, session: AsyncSession = Depends(get_session)):
+    meeting = await session.get(Meeting, meeting_id)
+    if not meeting:
+        raise HTTPException(404, "meeting not found")
+    await session.delete(meeting)
+    await session.commit()
+    return {"ok": True}