refactor(neotree): reuse native husk standard library

[fcoury-oai]

Why

Neo-tree still performs path normalization, Git-status decoration, and tree-row construction through compatibility helpers even though Husk now has a native standard library. Moving the pure presentation work into a native package makes it typed and directly testable while keeping permissioned filesystem actions and confirmations in the existing shell.

What Changed

• add the embedded, multi-file plugins/neotree_core package for normalized paths, typed status presentation, selection and clipboard markers, icons, and bounded tree rendering
• convert the host status index into sorted typed entries once at the bridge and use bounded lookup during rendering
• simplify plugins/neotree.hk while preserving workspace confinement, destructive-action confirmations, directory truncation, and the 200-row instruction-budget guard
• add native-core and embedded-bridge coverage, wire the Neo-tree suites into plugin CI, and document the new package

How to Test

Run the focused native and runtime regressions:

cargo run --all-features --locked -p husk-cli -- test --locked plugins/neotree_core
cargo test --all-features --locked -p red --lib plugin::runtime::tests::neotree_
cargo test --all-features --locked -p red --lib plugin::runtime::tests::embedded_neotree_core_

All tests should pass, including filesystem-root repositories, create/delete flows, large Git-status listings, and pathological directory listings capped at 200 rows.

Verify the bundled runtime and lint gate:

cargo fmt --all -- --check
cargo clippy --all-targets --all-features --locked -- -D warnings
cargo run --all-features --locked -- --self-check

The self-check should report plugin neotree: active and finish successfully.