release(1.2.0): stream responses and evaluate body return patterns

[rennf93]

Closes #35

• version 1.1.0 to 1.2.0, install snippets to 1.2.0.
• Minor bump: responses now stream unbuffered unless a body feature is active (fix(filter): stream responses unbuffered unless a body feature is active #34), so the guard no longer sets Content-Length on streamed responses. Body based return_pattern rules also evaluate.
• Engine unchanged: guard-core 4.4.0 and the pinned engine ref 7711606 stay as they are.
• CHANGELOG: Unreleased becomes [1.2.0] - 2026-10-17.

Local gate: ./gradlew spotlessApply detekt build --no-daemon --max-workers=2 0 with Redis on 6379, and no files changed by spotlessApply.