LR-PREF-PEOPLE: update pure-Rust recognition and preserve valid model replacements

Keep current upstream UI behavior and the later detector contract checks. Validate candidate models before replacing working weights and records, with a synthetic regression that failed before the fix. Remove the unrelated GPU equivalence-test relaxation. All seven quality gates pass with the pinned hosted fonts.

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apps/lightcraft-cli/Cargo.toml

@@ -25,6 +25,7 @@ serde_json = { workspace = true }
 dhat = { workspace = true, optional = true }
 
 [features]
+default = []
 # Heap profiling: `cargo run --release -p lightcraft-cli --features dhat-heap -- snapshot …` counts
 # every allocation (live/peak bytes in `library.memory` / `ui.inspect`) and writes dhat-heap.json
 # (open it in DHAT's viewer: allocation sites by bytes at the peak). Slows allocation-heavy work.