Python: Pin openrewrite Python package version in RPC bootstrap

[knutwannheden]

Summary

PythonRewriteRpc.bootstrapOpenrewrite() was running bare pip install openrewrite without a version specifier, unlike the JavaScript side which reads /META-INF/version.txt and pins @openrewrite/rewrite@<version> via npx. This could result in a mismatched Python openrewrite package, and the existence-only check meant users could get stuck on a stale version indefinitely.

Changes

• Version resource: Generate META-INF/version.txt at build time (PEP 440 format), matching the rewrite-javascript pattern. Wired into sourcesJar, processResources, licenseMain, assemble tasks. License exclude and .gitignore entry added.
• Version pinning: bootstrapOpenrewrite() reads the version from the resource and runs pip install --upgrade openrewrite==<version> for release/CI builds. For local .dev0 builds, the version is not pinned.
• Stale install detection: A .openrewrite-version marker file tracks the installed version in pipPackagesPath. On startup, if the marker doesn't match the JAR's version, the package is reinstalled with --upgrade.
• Dev interpreter detection: For SNAPSHOT/dev builds only, probes whether the Python interpreter can already import rewrite (e.g., from a venv with an editable install). If so, skips both bootstrap and PYTHONPATH prepend so the interpreter's own package takes precedence. This mirrors the JS pattern where SNAPSHOT trusts the local dev environment (npm link).

Behavior matrix

Build type	version.txt	Interpreter has rewrite?	Behavior
Release 8.75.0	8.75.0	(ignored)	Bootstrap openrewrite==8.75.0, prepend to PYTHONPATH
CI SNAPSHOT	8.75.0.dev2026...	(ignored)	Bootstrap pinned dev version, prepend to PYTHONPATH
Local SNAPSHOT	8.75.0.dev0	Yes (venv)	Skip bootstrap, skip prepend — use venv's package
Local SNAPSHOT	8.75.0.dev0	No	Bootstrap unpinned openrewrite, prepend to PYTHONPATH

Companion CLI PR: https://github.com/moderneinc/moderne-cli/pull/3350

Test plan

• ./gradlew :rewrite-python:assemble succeeds, version.txt present in JAR with correct content
• ./gradlew :rewrite-python:licenseFormat does not inject headers into version.txt
• Verify release build (non-SNAPSHOT) produces clean version like 8.75.0 in version.txt
• Verify bootstrap with pipPackagesPath set installs the pinned version
• Verify dev build with venv interpreter skips bootstrap and uses venv's package