Security: Mitigate GTK3 advisory chain from Tauri Linux runtime

[saagar210]

Tracking unmaintained GTK3 advisories currently pulled transitively by Tauri Linux runtime crates.

Advisories in this track:

• RUSTSEC-2024-0411
• RUSTSEC-2024-0412
• RUSTSEC-2024-0413
• RUSTSEC-2024-0415
• RUSTSEC-2024-0416
• RUSTSEC-2024-0418
• RUSTSEC-2024-0419
• RUSTSEC-2024-0420
• RUSTSEC-2024-0370 (proc-macro-error via GTK stack)

Current dependency chain evidence:

• tauri -> tauri-runtime-wry / wry -> webkit2gtk / gtk (Linux path)

Planned mitigation path:

1. Continue Tauri runtime upgrade watch for GTK4/non-GTK3 transitions.
2. Evaluate explicit Linux runtime policy (supported vs. feature-pruned path) with product owner.
3. Remove waivers as dependencies are retired.

Parent issue: #11