Jumoo.TranslationManager: v17.7.2 and v18.1.2 releases

v18: bumped Jumoo.TranslationManager.Microsoft to 18.1.0, Jumoo.TranslationManager.AI to 18.1.1, and Jumoo.Processing to 18.1.0; full build + test pass green (153 unit, 78 integration tests)
v18: audited v17/main vs v18/main for un-ported fixes — only the import-map duplicate-registration fix was outstanding, found it was already applied independently
v18: bumped version to 18.1.2, updated CHANGELOG.md, tagged release/v18.1.2
Published v18.1.2 release notes (translation memory correctness fixes, job-cancel crash guard, provider-selection validation fix) and backfilled the missing v17.7.2 changelog entry, both on the Issues repo
Cleaned up ~14 merged/stale branches off the main repo's remote (old v5/v6 main lines, absorbed v11 feature branches, shared/*), fast-forwarded local v17/main