feat(cli/server): hint --host 0.0.0.0 when bound to loopback

[RemiliaForever (RemiliaForever)]

Pull Request

Description

One of the four UX items from the customer feedback report in #1295, split out from #1255. Output-side only; no SDK changes.

• serve prints a hint line when bound to a loopback address (127.0.0.0/8, localhost, ::1), pointing users at --host 0.0.0.0:<port> to expose the server on the LAN.
• Non-loopback binds (0.0.0.0, [::], an explicit LAN IP) print nothing extra.
• Malformed hosts are treated as non-loopback — better silent than misleading.
• Replaces the placeholder package_test.go with server_test.go covering hostBindingHint.

Related Issue

Refs qualcomm/GenieX#1295 (item 5). Split out from #1255.

Type of Change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Additional Context

Verified manually on Windows ARM64 (Snapdragon X Elite): default bind printed the hint; --host 0.0.0.0:18181 printed no hint; [::1]:18181 printed the hint.