Initial commit with server startup infrastructure

Core infrastructure:
- Uber fx dependency injection
- Chi router with middleware stack
- SQLite database with embedded migrations
- Embedded templates and static assets
- Structured logging with slog

Features implemented:
- Authentication (login, logout, session management, argon2id hashing)
- App management (create, edit, delete, list)
- Deployment pipeline (clone, build, deploy, health check)
- Webhook processing for Gitea
- Notifications (ntfy, Slack)
- Environment variables, labels, volumes per app
- SSH key generation for deploy keys

Server startup:
- Server.Run() starts HTTP server on configured port
- Server.Shutdown() for graceful shutdown
- SetupRoutes() wires all handlers with chi router

internal/handlers/healthcheck.go

@@ -0,0 +1,12 @@
+package handlers
+
+import (
+	"net/http"
+)
+
+// HandleHealthCheck returns the health check handler.
+func (h *Handlers) HandleHealthCheck() http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		h.respondJSON(writer, request, h.hc.Check(), http.StatusOK)
+	}
+}