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/handler/media.go

@@ -11,9 +11,9 @@ import (
 
 	"github.com/gin-gonic/gin"
 
-	"github.com/ShukeBta/MMTL/internal/middleware"
-	"github.com/ShukeBta/MMTL/internal/model"
-	"github.com/ShukeBta/MMTL/internal/service"
+	"github.com/truewhile/MeBox/internal/middleware"
+	"github.com/truewhile/MeBox/internal/model"
+	"github.com/truewhile/MeBox/internal/service"
 )
 
 type createLibraryReq struct {
@@ -509,7 +509,7 @@ func streamHandler(svc *service.Container) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		ctx := c.Request.Context()
 		id := c.Param("id")
-		// 远程 Emby 条目：按挂载代理配置分流——代理走 MMTL 反代，否则 302 直连。
+		// 远程 Emby 条目：按挂载代理配置分流——代理走 MeBox 反代，否则 302 直连。
 		if svc.EmbyRemote != nil && service.IsEmbyRemoteID(id) {
 			if !enforceScopedPlaybackToken(c, id) {
 				return