Initial commit: webmail client (M0/M1)

Three-pane webmail client.
- Backend: FastAPI + async SQLAlchemy + arq worker (Postgres/Redis), IMAP/SMTP
  sync, threading, search, drafts/outbox with undo, attachments, 2FA.
- Frontend: React 18 + Vite + TypeScript + TanStack Query + Tailwind; three-pane
  UI with rich-text composer, light/dark themes, resizable panels.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,33 @@
+# Secrets / local env
+.env.dev
+.env.*.local
+gitea-server-credentials.md
+
+# Local tooling
+.claude/
+
+# Blob store / runtime data (email content — never commit)
+/var/
+/backend/var/
+**/var/blobs/
+
+# Python
+__pycache__/
+*.py[cod]
+.mypy_cache/
+.ruff_cache/
+.pytest_cache/
+*.egg-info/
+.eggs/
+build/
+dist/
+
+# Node / frontend
+node_modules/
+frontend/dist/
+.vite/
+
+# Editor / OS
+.DS_Store
+.idea/
+.vscode/