refactor: extract models/routes and env-based server config

- Move API request/response structs into new lib/models package
- Centralize Gin route registration in lib/routing to simplify wiring
- Add lib/server config helper to allow WARPBOX_BOX_POLL_INTERVAL_MS override
- Improves modularity and makes polling behavior configurable per environmentrefactor: extract models/routes and env-based server config

- Move API request/response structs into new lib/models package
- Centralize Gin route registration in lib/routing to simplify wiring
- Add lib/server config helper to allow WARPBOX_BOX_POLL_INTERVAL_MS override
- Improves modularity and makes polling behavior configurable per environment

lib/server/paths.go

@@ -0,0 +1,55 @@
+package server
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+func boxPath(boxID string) string {
+	return filepath.Join(uploadRoot, boxID)
+}
+
+func manifestPath(boxID string) string {
+	return filepath.Join(boxPath(boxID), boxManifestFile)
+}
+
+func safeFilename(name string) (string, bool) {
+	filename := filepath.Base(name)
+	filename = strings.TrimSpace(filename)
+	return filename, filename != "" && filename != "." && filename != string(filepath.Separator)
+}
+
+func safeBoxFilePath(boxID string, filename string) (string, bool) {
+	path := filepath.Join(boxPath(boxID), filename)
+	return path, strings.HasPrefix(path, boxPath(boxID)+string(filepath.Separator))
+}
+
+func uniqueFilename(directory string, filename string) string {
+	if _, err := os.Stat(filepath.Join(directory, filename)); os.IsNotExist(err) {
+		return filename
+	}
+
+	extension := filepath.Ext(filename)
+	base := strings.TrimSuffix(filename, extension)
+	for count := 2; ; count++ {
+		candidate := base + "-" + strconv.Itoa(count) + extension
+		if _, err := os.Stat(filepath.Join(directory, candidate)); os.IsNotExist(err) {
+			return candidate
+		}
+	}
+}
+
+func uniqueManifestFilename(filename string, usedNames map[string]int) string {
+	count := usedNames[filename]
+	usedNames[filename] = count + 1
+
+	if count == 0 {
+		return filename
+	}
+
+	extension := filepath.Ext(filename)
+	base := strings.TrimSuffix(filename, extension)
+	return base + "-" + strconv.Itoa(count+1) + extension
+}