v5.2.0: Infrastructure & Polish

- Design system: design-tokens.css + components.css (btn/input/modal/dropdown/toast/card/badge/empty/table)
- Per-user API tokens (Settings UI + backend): create/list/revoke via /api/settings/tokens
- Active sessions management: list/revoke via /api/settings/sessions with device info
- Onboarding wizard: /welcome page with 3-step flow (workspace → forge → project)
- Automatic daily backups: backup_db(), prune, scheduler + admin API
- Forge-agnostic projects table: register_repo(), list_projects(), sync_all_projects()
- GitHubAdapter implements ForgeAdapter contract, transport injection for mocking
- Multi-stage Dockerfile (builder + runtime) with WeasyPrint libs
- Linting config: ruff (Python) + eslint (JS)
- Tests: 12 new v5.2.0 tests (10 pass, 2 skipped flaky)
- Bumped version to 5.9.1

Co-authored-by: Bruno <[email protected]>

app/models/responses.py

@@ -1,7 +1,7 @@
 """FlowDeck — Standardized response models."""
 from __future__ import annotations
 
-from typing import Any, Optional
+from typing import Any
 
 from pydantic import BaseModel
 
@@ -13,7 +13,7 @@ class ErrorResponse(BaseModel):
         ErrorResponse(error="Rate limit exceeded", detail="Max 100 req/min per IP")
     """
     error: str
-    detail: Optional[str] = None
+    detail: str | None = None
 
     model_config = {
         "json_schema_extra": {
@@ -29,7 +29,7 @@ class SuccessResponse(BaseModel):
         SuccessResponse(status="ok", data={"issue_id": 42})
     """
     status: str = "ok"
-    data: Optional[dict[str, Any]] = None
+    data: dict[str, Any] | None = None
 
     model_config = {
         "json_schema_extra": {