feat(plugin): add WASM Component Model plugin system

.changeset/wasm-plugin-system.md

@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": minor
+---
+
+Added an opt-in WASM Component Model plugin system behind the `wasm_plugin` feature flag. Users can write custom lint rules in Rust (or any language targeting `wasm32-wasip2`), compile them to `.wasm` modules, and load them at runtime via `wasmtime`. Plugins support full AST traversal, semantic model access, type inference, configurable options, and suppression comments. This complements the existing GritQL plugin system with a high-performance alternative for complex rules that need stateful analysis.

.gitignore

@@ -33,3 +33,6 @@ dhat-heap.json
 !/crates/biome_json_formatter/tests/specs/prettier/**/*
 !/crates/biome_css_formatter/tests/specs/prettier/**/*
 !/crates/biome_graphql_formatter/tests/specs/prettier/**/*
+
+# Compiled WASM plugin test fixtures (built by biome_plugin_loader/build.rs)
+crates/biome_plugin_loader/tests/fixtures/*.wasm