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/config/config.go

@@ -0,0 +1,139 @@
+// Package config provides application configuration via Viper.
+package config
+
+import (
+	"errors"
+	"fmt"
+	"log/slog"
+
+	"github.com/spf13/viper"
+	"go.uber.org/fx"
+
+	"git.eeqj.de/sneak/upaas/internal/globals"
+	"git.eeqj.de/sneak/upaas/internal/logger"
+)
+
+// defaultPort is the default HTTP server port.
+const defaultPort = 8080
+
+// Params contains dependencies for Config.
+type Params struct {
+	fx.In
+
+	Globals *globals.Globals
+	Logger  *logger.Logger
+}
+
+// Config holds application configuration.
+type Config struct {
+	Port            int
+	Debug           bool
+	DataDir         string
+	DockerHost      string
+	SentryDSN       string
+	MaintenanceMode bool
+	MetricsUsername string
+	MetricsPassword string
+	SessionSecret   string
+	params          *Params
+	log             *slog.Logger
+}
+
+// New creates a new Config instance from environment and config files.
+func New(_ fx.Lifecycle, params Params) (*Config, error) {
+	log := params.Logger.Get()
+
+	name := params.Globals.Appname
+	if name == "" {
+		name = "upaas"
+	}
+
+	setupViper(name)
+
+	cfg, err := buildConfig(log, &params)
+	if err != nil {
+		return nil, err
+	}
+
+	configureDebugLogging(cfg, params)
+
+	return cfg, nil
+}
+
+func setupViper(name string) {
+	// Config file settings
+	viper.SetConfigName(name)
+	viper.SetConfigType("yaml")
+	viper.AddConfigPath("/etc/" + name)
+	viper.AddConfigPath("$HOME/.config/" + name)
+	viper.AddConfigPath(".")
+
+	// Environment variables override everything
+	viper.SetEnvPrefix("UPAAS")
+	viper.AutomaticEnv()
+
+	// Defaults
+	viper.SetDefault("PORT", defaultPort)
+	viper.SetDefault("DEBUG", false)
+	viper.SetDefault("DATA_DIR", "./data")
+	viper.SetDefault("DOCKER_HOST", "unix:///var/run/docker.sock")
+	viper.SetDefault("SENTRY_DSN", "")
+	viper.SetDefault("MAINTENANCE_MODE", false)
+	viper.SetDefault("METRICS_USERNAME", "")
+	viper.SetDefault("METRICS_PASSWORD", "")
+	viper.SetDefault("SESSION_SECRET", "")
+}
+
+func buildConfig(log *slog.Logger, params *Params) (*Config, error) {
+	// Read config file (optional)
+	err := viper.ReadInConfig()
+	if err != nil {
+		var configFileNotFoundError viper.ConfigFileNotFoundError
+		if !errors.As(err, &configFileNotFoundError) {
+			log.Error("config file malformed", "error", err)
+
+			return nil, fmt.Errorf("config file malformed: %w", err)
+		}
+		// Config file not found is OK
+	}
+
+	// Build config struct
+	cfg := &Config{
+		Port:            viper.GetInt("PORT"),
+		Debug:           viper.GetBool("DEBUG"),
+		DataDir:         viper.GetString("DATA_DIR"),
+		DockerHost:      viper.GetString("DOCKER_HOST"),
+		SentryDSN:       viper.GetString("SENTRY_DSN"),
+		MaintenanceMode: viper.GetBool("MAINTENANCE_MODE"),
+		MetricsUsername: viper.GetString("METRICS_USERNAME"),
+		MetricsPassword: viper.GetString("METRICS_PASSWORD"),
+		SessionSecret:   viper.GetString("SESSION_SECRET"),
+		params:          params,
+		log:             log,
+	}
+
+	// Generate session secret if not set
+	if cfg.SessionSecret == "" {
+		cfg.SessionSecret = "change-me-in-production-please"
+
+		log.Warn(
+			"using default session secret, " +
+				"set UPAAS_SESSION_SECRET in production",
+		)
+	}
+
+	return cfg, nil
+}
+
+func configureDebugLogging(cfg *Config, params Params) {
+	// Enable debug logging if configured
+	if cfg.Debug {
+		params.Logger.EnableDebugLogging()
+		cfg.log = params.Logger.Get()
+	}
+}
+
+// DatabasePath returns the full path to the SQLite database file.
+func (c *Config) DatabasePath() string {
+	return c.DataDir + "/upaas.db"
+}