Refactor to fix circular imports (#4700)

# Description of Changes
Refactors code to avoid circular imports everywhere and adds linting for
circular imports to ensure it doesn't happen again. Most changes are
around the tool registry, making it a provider, and splitting into tool
types to make it easier for things like Automate to only have access to
tools excluding itself.

frontend/src/constants/app.ts

@@ -1,10 +1,3 @@
-import { useAppConfig } from '../hooks/useAppConfig';
-
-// Get base URL from app config with fallback
-export const getBaseUrl = (): string => {
-  const { config } = useAppConfig();
-  return config?.baseUrl || 'https://stirling.com';
-};
 
 // Base path from Vite config - build-time constant, normalized (no trailing slash)
 // When no subpath, use empty string instead of '.' to avoid relative path issues