feat: add Python and Java regex engines

engines/java/README.md

@@ -0,0 +1,25 @@
+# TeaVM Java regular-expression engine
+
+This project compiles a bounded bridge around TeaVM 0.15.0's
+`java.util.regex.Pattern` and `Matcher` class-library implementation to a
+minified ES2015 module.
+
+The runtime is intentionally identified as `TeaVM java.util.regex 0.15.0`.
+TeaVM supplies its own Apache Harmony-derived Java class-library subset; the
+generated engine is not OpenJDK and must not be presented as exact OpenJDK
+semantics.
+
+The `U` application flag is a compatibility request. TeaVM 0.15.0 does not
+implement OpenJDK's `Pattern.UNICODE_CHARACTER_CLASS`; the bridge implies
+Unicode case folding but retains TeaVM's predefined-character-class and word
+boundary behaviour. The TypeScript adapter reports this boundary.
+
+Replacement is delegated to TeaVM 0.15.0's native `Matcher` implementation.
+That implementation recognizes only a single decimal digit after `$` (`$0`
+through `$9`, subject to the compiled group count). It does not implement
+OpenJDK's `${name}` named-replacement syntax; the bridge returns a
+`replacement-error` when such a replacement is attempted.
+
+Maven builds `target/generated/java-regex.mjs`. The repository pack script
+verifies the pinned source identity, bridge source hashes, licence/notice and
+generated module before it can be installed under `public/engines/java`.