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_compat.go

@@ -3,7 +3,7 @@
 // EmbyService produces JSON envelopes shaped like the most-consumed
 // Emby-API endpoints so existing players (Infuse / Yamby / Hills /
 // Senplayer / Kodi NextPVR extension / iOS native clients) can talk to
-// MMTL without a custom plugin.
+// MeBox without a custom plugin.
 //
 // The shim is read-mostly: items, images, playback are fully covered;
 // 播放进度上报 / 收藏切换 是写路径但走我们自己的 PlaybackHistory /
@@ -17,14 +17,14 @@ import (
 	"sync"
 	"time"
 
-	"github.com/ShukeBta/MMTL/internal/config"
-	"github.com/ShukeBta/MMTL/internal/repository"
+	"github.com/truewhile/MeBox/internal/config"
+	"github.com/truewhile/MeBox/internal/repository"
 	"go.uber.org/zap"
 )
 
 // 用一个固定的 ServerId 字符串。Emby 客户端会缓存这个 id，第一次见到
 // 该 id 后会把所有派生数据（cookie/收藏/历史）和它绑定。
-const embyServerID = "mmtl-001"
+const embyServerID = "mebox-001"
 
 // embyCompatVersion deliberately reports an Emby 4.x server. Official Emby
 // clients reject Jellyfin-style 10.x identities as unsupported/too old during