feat: add Python and Java regex engines

SOURCE.md

@@ -1,10 +1,10 @@
 # Source identity
 
 - Project: Regex Tools
-- Release version: `0.2.0`
-- Release tag: `v0.2.0`
+- Release version: `0.3.0`
+- Release tag: `v0.3.0`
 - Repository: <https://git.add-ideas.de/zemion/regex-tools>
-- Previous release tag: `v0.1.0`
+- Previous release tag: `v0.2.0`
 - Licence: GPL-3.0-or-later
 - Copyright: © 2026 Albrecht Degering
 
@@ -20,14 +20,26 @@ runtime or build-time CDN fetch. Complete preferred-form source is the tagged
 repository. The release archive contains compiled static assets plus legal,
 source-identity and attribution documents.
 
-The explicit offline PCRE2 build is documented in `docs/ENGINE_BUILDS.md`.
-PCRE2 source is not vendored: the gate accepts only the pinned, clean official
-10.47 checkout and Emscripten 6.0.4 compiler. Generated staging is ignored; the
-verified runtime files, deterministic metadata, checksums and exact licence are
-installed under `public/engines/pcre2/` and included in the application source
-and build.
+The engine-pack inputs and rebuild gates are documented in
+`docs/ENGINE_BUILDS.md`.
 
-The v0.2.0 release includes PCRE2. Python, Go, Rust, .NET, Java and legacy PCRE
-remain unimplemented. The v0.1.0 release remains available under its historical
-tag and artifact coordinates. A future public artifact must bump package,
-manifest, tag and source identity together; it must not reuse `v0.2.0`.
+- PCRE2 source is not vendored: the gate accepts only the pinned, clean
+  official 10.47 checkout and Emscripten 6.0.4 compiler.
+- The Python pack is copied from the exact pinned Pyodide 314.0.3 npm package
+  and contains its CPython 3.14.2 runtime, Python standard library, loader,
+  WebAssembly module, metadata, checksums and licence material.
+- The Java bridge source is under `engines/java/`. Its bundled module is
+  compiled against TeaVM 0.15.0's `java.util.regex` class library and is
+  identified as TeaVM rather than OpenJDK.
+
+Generated staging is ignored. Only verified runtime packs with deterministic
+metadata, closed file sets, checksums and exact licence/notice material are
+installed under `public/engines/` and included in the application source and
+build.
+
+The v0.3.0 release includes native browser ECMAScript, PCRE2 10.47, CPython
+3.14.2 `re` through Pyodide 314.0.3 and TeaVM 0.15.0 `java.util.regex`. Go,
+Rust, .NET and legacy PCRE remain unimplemented. Earlier releases remain
+available under their historical tags and artifact coordinates. A future
+public artifact must bump package, manifest, tag and source identity together;
+it must not reuse `v0.3.0`.