Add vue-router, login/setup flow and backend logging

Refactor frontend to route-based navigation with vue-router, add
system setup and login pages with API integration. Add structured
logging, access-log middleware and startup lifecycle to FastAPI
backend.

server/src/app/core/config.py

@@ -44,7 +44,13 @@ class Settings(BaseSettings):
 
     redis_url: str | None = Field(default=None, alias="REDIS_URL")
     cors_origins: list[str] = Field(default_factory=list, alias="CORS_ORIGINS")
-    vite_api_base_url: str = Field(default="http://127.0.0.1:8000/api/v1", alias="VITE_API_BASE_URL")
+    vite_api_base_url: str = Field(
+        default="http://127.0.0.1:8000/api/v1", alias="VITE_API_BASE_URL"
+    )
+
+    log_level: str = Field(default="INFO", alias="LOG_LEVEL")
+    log_dir: str = Field(default="logs", alias="LOG_DIR")
+    log_file_enabled: bool = Field(default=True, alias="LOG_FILE_ENABLED")
 
     @property
     def resolved_database_url(self) -> str: