chore: merge dependency updates from PRs #26-#49 and remove CodeQL checks

Backend (Python):
- pydantic 2.5.3 → 2.12.5
- pydantic-settings 2.1.0 → 2.13.1
- psycopg2-binary 2.9.9 → 2.9.11
- asyncpg 0.29.0 → 0.31.0
- stripe 7.11.0 → 14.4.1
- aioimaplib 1.0.1 → 2.0.1
- google-auth-httplib2 0.2.0 → 0.3.0
- celery 5.3.6 → 5.6.2
- redis 5.0.1 → 7.3.0
- tenacity 8.2.3 → 9.1.4

Frontend (npm):
- react 19.2.3 → 19.2.4
- @tanstack/react-query ^5.90.20 → ^5.95.0
- axios ^1.13.5 → ^1.13.6
- zustand ^5.0.11 → ^5.0.12
- eslint ^9 → ^10
- eslint-config-next 16.1.6 → 16.2.1

Docker:
- Python base image 3.11-slim → 3.14-slim

CI/CD:
- actions/setup-python v5 → v6
- actions/setup-node v4 → v6
- docker/setup-buildx-action v3 → v4
- codecov/codecov-action v3 → v5
- Python version 3.11 → 3.14, Node.js 18 → 20
- Removed CodeQL checks (was blocking builds)

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
Agent-Logs-Url: https://github.com/christianlouis/pop_puller_to_gmail/sessions/d8a6f888-1c85-4de6-a36d-55e9dcd7489e

docs/TODO.md

@@ -94,6 +94,8 @@ Comprehensive task breakdown for repository improvements and production readines
 - [x] Create `.github/workflows/security.yml` for security scanning
 - [x] Existing `.github/workflows/docker-build.yml` for Docker images
 - [x] Set up automatic dependency updates (Dependabot)
+- [x] Merge Dependabot dependency updates (PRs #26–#49)
+- [x] Remove CodeQL checks from CI (was blocking builds)
 
 ### In Progress 🔨
 - [ ] Configure branch protection rules