opdiff v0.1.0

First release. opdiff <ref1>..<ref2> prints an operator upgrade checklist derived from source, with no checkout, no network, and no LLM:

• Env vars: added / removed / likely-renamed read sites across JS/TS (process.env), Python (os.environ, os.getenv), and Go (os.Getenv, os.LookupEnv), each with a file:line.
• Migrations: new files under common migration directories.
• Ports: Dockerfile EXPOSE, compose ports: entries, listen-port literals.
• Base images: FROM changes, multi-stage aware, same-repo bumps paired as old -> new.

Plus --json for CI. Zero dependencies, Node >=18.

Validated cold on gitea v1.25.0..v1.26.0: it found 8 new schema migrations, the golang 1.25 -> 1.26 and alpine 3.22 -> 3.23 base image bumps, and two genuine env var renames (GITEA_CONF -> GITEA_TEST_CONF, GITEA_UNIT_TESTS_LOG_SQL -> GITEA_TEST_LOG_SQL). See the README for the full transcript.