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>

backend/app/accounts/schemas.py

@@ -0,0 +1,74 @@
+"""Request/response models for the accounts API (SPEC §9.1)."""
+
+from __future__ import annotations
+
+import uuid
+
+from pydantic import BaseModel, Field
+
+
+class ServerConfigIn(BaseModel):
+    host: str
+    port: int = Field(ge=1, le=65535)
+    tls: str = "ssl"  # ssl | starttls
+    auth: str = "password"  # password | oauth2
+
+
+class DiscoverRequest(BaseModel):
+    email: str
+
+
+class CandidateOut(BaseModel):
+    imap: ServerConfigIn
+    smtp: ServerConfigIn
+    source: str
+    oauth_provider: str | None = None
+
+
+class DiscoveryStepOut(BaseModel):
+    method: str
+    status: str
+    detail: str = ""
+
+
+class DiscoverResponse(BaseModel):
+    candidates: list[CandidateOut]
+    steps: list[DiscoveryStepOut]
+
+
+class TestRequest(BaseModel):
+    imap: ServerConfigIn
+    smtp: ServerConfigIn
+    email: str
+    username: str | None = None  # defaults to the email address
+    password: str = Field(min_length=1)
+
+
+class TestResponse(BaseModel):
+    ok: bool = True
+
+
+class CreateAccountRequest(BaseModel):
+    email: str
+    display_name: str = ""
+    color: str = "#888888"
+    imap: ServerConfigIn
+    smtp: ServerConfigIn
+    username: str | None = None
+    password: str = Field(min_length=1)
+
+
+class UpdateAccountRequest(BaseModel):
+    display_name: str | None = None
+    color: str | None = None
+
+
+class AccountDetailOut(BaseModel):
+    id: uuid.UUID
+    email: str
+    display_name: str
+    color: str
+    state: str
+    state_detail: str
+    imap_config: dict[str, object]
+    smtp_config: dict[str, object]