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/healthcheck/healthcheck.go

@@ -0,0 +1,85 @@
+// Package healthcheck provides application health status.
+package healthcheck
+
+import (
+	"context"
+	"log/slog"
+	"time"
+
+	"go.uber.org/fx"
+
+	"git.eeqj.de/sneak/upaas/internal/config"
+	"git.eeqj.de/sneak/upaas/internal/database"
+	"git.eeqj.de/sneak/upaas/internal/globals"
+	"git.eeqj.de/sneak/upaas/internal/logger"
+)
+
+// Params contains dependencies for Healthcheck.
+type Params struct {
+	fx.In
+
+	Globals  *globals.Globals
+	Config   *config.Config
+	Logger   *logger.Logger
+	Database *database.Database
+}
+
+// Healthcheck provides health status information.
+type Healthcheck struct {
+	StartupTime time.Time
+	log         *slog.Logger
+	params      *Params
+}
+
+// Response is the health check response structure.
+type Response struct {
+	Status        string `json:"status"`
+	Now           string `json:"now"`
+	UptimeSeconds int64  `json:"uptimeSeconds"`
+	UptimeHuman   string `json:"uptimeHuman"`
+	Version       string `json:"version"`
+	Appname       string `json:"appname"`
+	Maintenance   bool   `json:"maintenanceMode"`
+}
+
+// New creates a new Healthcheck instance.
+func New(lifecycle fx.Lifecycle, params Params) (*Healthcheck, error) {
+	healthcheck := &Healthcheck{
+		log:    params.Logger.Get(),
+		params: &params,
+	}
+
+	// For testing, if lifecycle is nil, initialize immediately
+	if lifecycle == nil {
+		healthcheck.StartupTime = time.Now()
+
+		return healthcheck, nil
+	}
+
+	lifecycle.Append(fx.Hook{
+		OnStart: func(_ context.Context) error {
+			healthcheck.StartupTime = time.Now()
+
+			return nil
+		},
+	})
+
+	return healthcheck, nil
+}
+
+// Check returns the current health status.
+func (h *Healthcheck) Check() *Response {
+	return &Response{
+		Status:        "ok",
+		Now:           time.Now().UTC().Format(time.RFC3339Nano),
+		UptimeSeconds: int64(h.uptime().Seconds()),
+		UptimeHuman:   h.uptime().String(),
+		Appname:       h.params.Globals.Appname,
+		Version:       h.params.Globals.Version,
+		Maintenance:   h.params.Config.MaintenanceMode,
+	}
+}
+
+func (h *Healthcheck) uptime() time.Duration {
+	return time.Since(h.StartupTime)
+}