Sentinel AEGIS v3.9.6 - Trust Gate Tuning

Changes:
- Added three-tier Network Trust Gate: TRUSTED / UNCERTAIN / UNTRUSTED.
- A single weak network flag no longer forces the hard challenge.
- UNCERTAIN traffic receives a silent/light proof check and then follows the normal user CAPTCHA preference.
- Hard challenge is reserved for high-confidence network risk or elevated exact-IP behavior.
- Subnet/ASN elevation by itself does not force the hard challenge.
- Hard verification now accepts either a normal click/tap or a press-and-hold gesture.
- Press-and-hold works with Pointer Events and includes mouse/touch fallback handlers.
- User CAPTCHA ON/OFF remains independent from the Network Trust Gate.

Defensive-use note:
This layer is intended for ordinary anti-abuse and traffic verification. It does not provide alternate destinations based on crawler/security-scanner identity.