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>

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

web/src/types/strm.ts

@@ -27,7 +27,7 @@ export interface StrmAccount {
   has_credential: boolean
   provider_label: string
   config_preview?: StrmAccountConfigPreview
-  /** 仅远程 Emby 挂载账号返回：播放流量是否经过 MMTL 代理 */
+  /** 仅远程 Emby 挂载账号返回：播放流量是否经过 MeBox 代理 */
   proxy_play?: boolean
   /** 仅远程 Emby 挂载账号返回：多线路配置 */
   emby_lines?: EmbyRemoteLine[]