patch: v0.1.1 + rey-compiler skeleton

[IMisbahk]

What

• Fix match patterns for structs and enum variants (qualified + unqualified).
• Fix import edge cases (per-item spans for grouped imports, nested module resolution fixtures/tests).
• Fix numeric semantics (int vs float runtime values, correct / behavior) and allow external mutation of pub struct fields.
• Add rey-compiler/ v5 bootstrap skeleton (API only).
• Bump v1 compiler crate to 0.1.1 and add compiler/README.md + docs/changelog updates.

Why

These unblock real-world code using match/imports and make numeric behavior consistent, while laying down the bootstrap compiler API surface for the v5 roadmap.

Notes

• Added a small Rust test harness in compiler/v1 to execute new .rey regression programs.
• Verification: cargo test and cargo build --release (compiler/v1).