Move StartTime initialization to application startup hook

- Remove StartTime initialization from globals.New()
- Add setupGlobals function in app.go to set StartTime during fx OnStart
- Simplify globals package to be just a key/value store
- Remove fx dependencies from globals test

internal/cli/app.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"git.eeqj.de/sneak/vaultik/internal/config"
 	"git.eeqj.de/sneak/vaultik/internal/database"
@@ -17,6 +18,16 @@ type AppOptions struct {
 	Invokes    []fx.Option
 }
 
+// setupGlobals sets up the globals with application startup time
+func setupGlobals(lc fx.Lifecycle, g *globals.Globals) {
+	lc.Append(fx.Hook{
+		OnStart: func(ctx context.Context) error {
+			g.StartTime = time.Now()
+			return nil
+		},
+	})
+}
+
 // NewApp creates a new fx application with common modules
 func NewApp(opts AppOptions) *fx.App {
 	baseModules := []fx.Option{
@@ -24,6 +35,7 @@ func NewApp(opts AppOptions) *fx.App {
 		fx.Provide(globals.New),
 		config.Module,
 		database.Module,
+		fx.Invoke(setupGlobals),
 		fx.NopLogger,
 	}