Rebrand MMTL to MeBox (name, logo, Docker image) (#17)

* Rebrand MMTL to MeBox across codebase and assets

Rename the project display name, Go module path, environment variable
prefix (MEBOX_*), Docker image references, and UI branding from MMTL/mmtl
to MeBox/mebox. Replace logo assets with the new MeBox icon and keep
legacy SQLite migration support for existing mmtl.db deployments.

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Fix logo icons: use cube-only crop without truncated text

Previous icon generation cropped too much of the source image, including
partial MeBox wordmark text that was cut off in square icon containers.
Regenerate logo-64/192/512, favicon, and SVG from cube-only region.

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: truewhile <truewhile@users.noreply.github.com>

internal/service/emby_system.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/ShukeBta/MMTL/internal/model"
+	"github.com/truewhile/MeBox/internal/model"
 )
 
 // SystemInfo returns the full Emby identity payload.
@@ -13,7 +13,7 @@ func (e *EmbyService) SystemInfo() map[string]any {
 	return map[string]any{
 		"Id":                     embyServerID,
 		"ServerId":               embyServerID,
-		"ServerName":             "MMTL",
+		"ServerName":             "MeBox",
 		"Version":                embyCompatVersion,
 		"ServerVersion":          embyCompatVersion,
 		"ProductName":            "Emby Server",
@@ -42,7 +42,7 @@ func (e *EmbyService) SystemInfoPublic() map[string]any {
 	return map[string]any{
 		"Id":                     embyServerID,
 		"ServerId":               embyServerID,
-		"ServerName":             "MMTL",
+		"ServerName":             "MeBox",
 		"Version":                embyCompatVersion,
 		"ServerVersion":          embyCompatVersion,
 		"ProductName":            "Emby Server",
@@ -85,7 +85,7 @@ func (e *EmbyService) userPayload(u *model.User) map[string]any {
 		"Id":                        u.ID,
 		"Name":                      u.Username,
 		"ServerId":                  embyServerID,
-		"ServerName":                "MMTL",
+		"ServerName":                "MeBox",
 		"HasPassword":               true,
 		"HasConfiguredPassword":     true,
 		"HasConfiguredEasyPassword": false,