Overhaul: real metrics, Git integration UI, open-source hygiene, root cleanup

Backend:
- GET /services/:id/metrics with real Docker container stats
- DELETE /git/providers/:id and GET repo branches endpoint

Frontend:
- Service detail shows real telemetry or honest empty states
- Live status distinguishes idle/polling/reconnecting
- Git providers section in Settings; repo+branch pickers in Add Service
- Real logo, compact Projects header, canvas fitView fix
- index.css deduplicated (1725 -> 1384 lines)
- Fixed smoke tests, lint errors, ToastProvider/context unification

Repo hygiene:
- Added LICENSE (MIT), CONTRIBUTING.md, SECURITY.md; rewrote README
- Untracked .env.prod and data/letsencrypt secrets; fixed .gitignore
- Removed legacy root src/internal/cmd and stale configs/docs/artifacts
- Moved guides and design references under docs/

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/frontend/src/shared/hooks/use-toast.ts

@@ -3,7 +3,7 @@ import { createContext, useContext } from 'react';
 export type ToastType = 'success' | 'info' | 'warning' | 'error';
 
 export interface ToastContextValue {
-  showToast: (message: string, type?: ToastType) => void;
+  showToast: (first: ToastType | string, second: ToastType | string, description?: string) => void;
 }
 
 export const ToastContext = createContext<ToastContextValue | null>(null);
@@ -11,7 +11,7 @@ export const ToastContext = createContext<ToastContextValue | null>(null);
 export function useToast() {
   const context = useContext(ToastContext);
   if (!context) {
-    throw new Error('useToast must be used within a ToastProvider');
+    throw new Error('useToast must be used within ToastProvider');
   }
   return context;
 }