feat(telegram): add telEgo backend

[Scratch-net]

Add telEgo v0.6.8 as a Hiddify Telegram proxy backend, with verified release archives for AMD64 and ARM64.

The service:

• listens on Hiddify's existing private port 127.0.0.1:1001;
• accepts PROXY protocol from the public layer-4 frontend;
• configures the shared secret and one UUID secret per user;
• exposes per-user Prometheus traffic counters at 127.0.0.1:10087/metrics.

The branch includes the current Manager dev branch. The PR remains limited to the telEgo service files and package entries.

Depends on hiddify/hiddifypanel#36, which adds the panel selector, per-user links, and usage accounting. That PR is still open. After it merges, services/panel/src must reference a panel commit containing those changes before this PR can merge.

This integration enables MTProxy. Native WEB carrier support needs separate frontend and panel settings changes to configure an owned hostname and its TLS certificate.

Validation completed with v0.6.8 on 2026-10-02:

• downloaded both release archives and matched their SHA-256 hashes to the published checksum file and package entries;
• checked the executable and ELF architecture in each archive, and ran the AMD64 binary's version command;
• rendered the Jinja configuration with zero and two users, parsed the TOML, and checked the secrets, PROXY protocol setting, mask hostname, and private listeners;
• started the AMD64 binary with the rendered configuration, connected to the proxy listener, fetched metrics with HTTP 200, and confirmed clean SIGTERM shutdown;
• checked the rendered backend selection scripts and all telEgo shell scripts with bash -n;
• checked the diff for whitespace errors.

The startup check used -b 127.0.0.1:11001 because the test account cannot bind port 1001. The committed configuration retains port 1001. ARM64 execution and a full Hiddify installation were not tested.