feat(site): add Trust & Safety section

[Codex4607]

What & why

Added a Trust & Safety section to the site homepage.

The section explains the safety flow as:
Scan → Review → Quarantine

It also highlights that safety verdicts are rule-based and gives users visibility and control before files are quarantined.

Checklist

• cargo fmt --all and cargo clippy --workspace are clean (not applicable: site-only change)
• cargo test --workspace passes (not applicable: site-only change)
• Commits are small and focused (one logical change each)
• Doesn't weaken a safety principle (read-only scans, quarantine over deletion, deterministic verdicts)
• User-visible changes are documented in CHANGELOG.md under Unreleased
• PR dependencies and overlapping component edits are identified
• Applicable CI passes; use the merge queue once it is enabled

[Muawiya-contact]

@LouisDeconinck Can you review it please.