Kotlin Multiplatform port of dtolnay/unicode-ident.

The upstream Rust crate exposes two predicates that determine whether a Unicode code point belongs to the XID_Start or XID_Continue property classes defined in Unicode Standard Annex #31, which is the property set Rust (and most other modern languages) use to decide which characters may begin or continue an identifier.

import io.github.kotlinmania.unicodeident.isXidStart
import io.github.kotlinmania.unicodeident.isXidContinue

This port is consumed by proc-macro2-kotlin for identifier validation in the Fallback token-parser, mirroring the unicode_ident::is_xid_start / unicode_ident::is_xid_continue calls in the upstream Rust fallback.rs.

Kotlin Multiplatform: macOS arm64, Linux x64, mingw x64, iOS arm64 / x64 / simulator-arm64, JS (browser + Node), Wasm-JS (browser + Node), Android. There is no JVM-only target.

./gradlew build
./gradlew test

Upstream unicode-ident is (MIT OR Apache-2.0) AND Unicode-3.0. The same combination applies to this port. License texts are mirrored from upstream as LICENSE-APACHE, LICENSE-MIT, and LICENSE-UNICODE.

Upstream README is preserved verbatim as README-UPSTREAM.md.

Bootstrap. Build infrastructure seeded from starlark-kotlin; no Kotlin source code has been ported yet. The next pass translates src/lib.rs and src/tables.rs into the commonMain package.