feat(telegram): add telEgo backend

[Scratch-net]

Add telEgo v0.5.4 as a Hiddify Telegram proxy backend.

The service:

• installs verified AMD64 and ARM64 release archives;
• 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 on 127.0.0.1:10087.

Depends on hiddify/hiddifypanel#36, which adds the panel selector, per-user links, and usage accounting. After that PR merges, this branch must update the Panel submodule before this PR is ready to merge.

The initial integration enables MTProxy only. Hiddify's current Telegram fake-domain setting is an external FakeTLS mask, not an owned WEB hostname with a certificate. Native WEB carrier support therefore needs a separate frontend and panel settings change.

Validation completed:

• verified both release archive SHA-256 hashes;
• extracted and ran the v0.5.4 AMD64 binary;
• rendered the Jinja template and parsed the resulting TOML;
• started telEgo with the rendered settings and reached its metrics endpoint;
• checked all shell scripts with bash -n.