feat: postgresql migration and removal of sqlite in pytest (#546)

* feat: remove support of sqlite, 100% postgres

* fix: more migration and make datetime timezone aware in postgres

* fix: change how database is get, and use contextvar to have difference instance between different loops

* test: properly use client fixture that handle lifetime/database connection

* fix: add missing client fixture parameters to test functions

This commit fixes NameError issues where test functions were trying to use
the 'client' fixture but didn't have it as a parameter. The changes include:

1. Added 'client' parameter to test functions in:
   - test_transcripts_audio_download.py (6 functions including fixture)
   - test_transcripts_speaker.py (3 functions)
   - test_transcripts_upload.py (1 function)
   - test_transcripts_rtc_ws.py (2 functions + appserver fixture)

2. Resolved naming conflicts in test_transcripts_rtc_ws.py where both HTTP
   client and StreamClient were using variable name 'client'. StreamClient
   instances are now named 'stream_client' to avoid conflicts.

3. Added missing 'from reflector.app import app' import in rtc_ws tests.

Background: Previously implemented contextvars solution with get_database()
function resolves asyncio event loop conflicts in Celery tasks. The global
client fixture was also created to replace manual AsyncClient instances,
ensuring proper FastAPI application lifecycle management and database
connections during tests.

All tests now pass except for 2 pre-existing RTC WebSocket test failures
related to asyncpg connection issues unrelated to these fixes.

* fix: ensure task are correctly closed

* fix: make separate event loop for the live server

* fix: make default settings pointing at postgres

* build: remove pytest-docker deps out of dev, just tests group

.github/workflows/db_migrations.yml

@@ -17,10 +17,40 @@ on:
 jobs:
   test-migrations:
     runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgres:17
+        env:
+          POSTGRES_USER: reflector
+          POSTGRES_PASSWORD: reflector
+          POSTGRES_DB: reflector
+        ports:
+          - 5432:5432
+        options: >-
+          --health-cmd pg_isready -h 127.0.0.1 -p 5432
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+
+    env:
+      DATABASE_URL: postgresql://reflector:reflector@localhost:5432/reflector
 
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install PostgreSQL client
+        run: sudo apt-get update && sudo apt-get install -y postgresql-client | cat
+
+      - name: Wait for Postgres
+        run: |
+          for i in {1..30}; do
+            if pg_isready -h localhost -p 5432; then
+              echo "Postgres is ready"
+              break
+            fi
+            echo "Waiting for Postgres... ($i)" && sleep 1
+          done
+
       - name: Install uv
         uses: astral-sh/setup-uv@v3
         with: