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/handlers.go

@@ -0,0 +1,76 @@
+// Package handlers provides HTTP request handlers.
+package handlers
+
+import (
+	"encoding/json"
+	"log/slog"
+	"net/http"
+
+	"go.uber.org/fx"
+
+	"git.eeqj.de/sneak/upaas/internal/database"
+	"git.eeqj.de/sneak/upaas/internal/globals"
+	"git.eeqj.de/sneak/upaas/internal/healthcheck"
+	"git.eeqj.de/sneak/upaas/internal/logger"
+	"git.eeqj.de/sneak/upaas/internal/service/app"
+	"git.eeqj.de/sneak/upaas/internal/service/auth"
+	"git.eeqj.de/sneak/upaas/internal/service/deploy"
+	"git.eeqj.de/sneak/upaas/internal/service/webhook"
+)
+
+// Params contains dependencies for Handlers.
+type Params struct {
+	fx.In
+
+	Logger      *logger.Logger
+	Globals     *globals.Globals
+	Database    *database.Database
+	Healthcheck *healthcheck.Healthcheck
+	Auth        *auth.Service
+	App         *app.Service
+	Deploy      *deploy.Service
+	Webhook     *webhook.Service
+}
+
+// Handlers provides HTTP request handlers.
+type Handlers struct {
+	log        *slog.Logger
+	params     *Params
+	db         *database.Database
+	hc         *healthcheck.Healthcheck
+	auth       *auth.Service
+	appService *app.Service
+	deploy     *deploy.Service
+	webhook    *webhook.Service
+}
+
+// New creates a new Handlers instance.
+func New(_ fx.Lifecycle, params Params) (*Handlers, error) {
+	return &Handlers{
+		log:        params.Logger.Get(),
+		params:     &params,
+		db:         params.Database,
+		hc:         params.Healthcheck,
+		auth:       params.Auth,
+		appService: params.App,
+		deploy:     params.Deploy,
+		webhook:    params.Webhook,
+	}, nil
+}
+
+func (h *Handlers) respondJSON(
+	writer http.ResponseWriter,
+	_ *http.Request,
+	data any,
+	status int,
+) {
+	writer.Header().Set("Content-Type", "application/json")
+	writer.WriteHeader(status)
+
+	if data != nil {
+		err := json.NewEncoder(writer).Encode(data)
+		if err != nil {
+			h.log.Error("json encode error", "error", err)
+		}
+	}
+}