v1.2.0 — transactional back stack writes

ForgeNav 1.2.0

Transactional back stack writes (N-BS-12).

Coordinates

studio.forgenav:forgenv-core:1.2.0
studio.forgenav:forgenv-compose:1.2.0
studio.forgenav:forgenv-syncforge:1.2.0
studio.forgenav:forgenv-testing:1.2.0

Changed

• Full stack as read model, ops as write path — multi-step mutations apply as a single transaction
• BackStackOp + BackStack.apply — op fold with BackStackApplyResult
• Single emission for setBackStack, deep-link stack rebuild, multi-pop, popUpTo+navigate
• App-facing ForgeNavigator methods unchanged

Design: docs/BACKSTACK_TRANSACTIONS.md
Full notes: CHANGELOG.md § 1.2.0