[FEATURE] Show MAX not CURRENT CPU GHz

[Flegma]

Right now we show current CPU GHz (/proc/cpuinfo) - we need to have another approach here, so its best to revert back to functionality that it was before and have this new one as a fallback.

[Flegma]

Proposed Change

File: game-server-node-connector/src/system/system.service.ts — only getCPUFrequncyInfo() needs to change.

Current behavior (after d57a997)

The code collects CPU frequency from two categories of sources:

1. Static sources (tried in order): CPU model name → dmidecode → lscpu — these report the rated/max clock
2. Live source: /proc/cpuinfo cpu MHz entries — reports the current running frequency per core

It then compares both and picks the highest. The problem is that on systems where cores are idling or running at variable speeds, /proc/cpuinfo may report the current (possibly boosted) frequency rather than the max rated frequency — leading to inconsistent/fluctuating values.

Proposed behavior

Revert to the old priority: use the first successful static source (model name → dmidecode → lscpu). Only fall back to /proc/cpuinfo max when no static source is available.

Keep the good fixes from d57a997:

• The string return type (was incorrectly typed as Record<number, string> before)
• The empty-array guard that prevented Infinity GHz on non-Linux systems
• Per-core live frequencies still reported in the cpus field for the UI

After the change

Static source found? → Use it (e.g. "3.7" from model name)
No static source?    → Use max of /proc/cpuinfo per-core values (with empty-array guard)
Neither available?   → "unknown"

This gives a stable, rated max frequency when available and only falls back to the live frequency when the system doesn't expose static info. No changes needed in the API or web frontend — they already handle the string frequency type.