worker: optional PyGhidra back-end for Ghidra 11.4+/12.x (no Jython)

The .py extractor runs fine under PyGhidra in the GUI; only `analyzeHeadless`
doesn't init PyGhidra. Add an env-gated CPython path so modern Ghidra works headless:

- ghidra.run_extractor_pyghidra(): runs the same GhidraScript via pyghidra.run_script
  (boots Ghidra in-process, imports+analyses, getScriptArgs()=[out_path]); run_extractor
  dispatches to it when AMS_USE_PYGHIDRA is set. No script changes needed.
- worker image installs pyghidra + sets GHIDRA_INSTALL_DIR; compose exposes
  AMS_USE_PYGHIDRA (default off). Jython path stays the default and untouched.
- README documents both variants (Jython <=11.3.x vs PyGhidra 11.4+/12.x).
- test: AMS_USE_PYGHIDRA routes to the PyGhidra back-end (clear error if pkg missing).

35/35 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker-compose.yml

@@ -59,6 +59,9 @@ services:
       DATABASE_URL: postgresql+psycopg://ams:ams@db:5432/ams
       REDIS_URL: redis://redis:6379/0
       AMS_UPLOAD_DIR: /data/uploads
+      # Set to 1 (e.g. `AMS_USE_PYGHIDRA=1 docker compose up`) to run the extractor through
+      # PyGhidra instead of Jython - needed for Ghidra 11.4+/12.x (build worker with that GHIDRA_URL).
+      AMS_USE_PYGHIDRA: ${AMS_USE_PYGHIDRA:-}
     volumes:
       - uploads:/data/uploads
     depends_on: