Rust intermission camera placement

RE-845. Reproduce with python3 scripts/analyze_rust_camera_place.py; focused validation: cargo xtask test-group rust-camera-place. Machine report.

Rust matches all 72 original camera fixtures, copying raw float words exactly and clearing the verified fields. The parity adapter resolves either entity-to-client target; the library accepts an already-resolved mutable client. Native camera/rendering and unrestricted pointer alias behavior remain open.

Original executable/native runtime and complete Linux/macOS Rust/Bevy/Solari acceptance remain unverified.