Local-First Sync Conflict Lab

Fix deletion-versus-null handling and add visual conflict choices, hash-bound replay and opt-in keyed-array identity contracts.

sync-conflict-lab base.json local.json remote.json --format html --output review.html

The HTML review shows base/local/remote values with explicit absence indicators and lets you download selected local/remote decisions. --replay accepts that version 1 plan only when all three input SHA-256 hashes match, using manual policy and the saved keyed_arrays contract. --keyed-arrays maps JSON pointers (root or object-field arrays) to a non-empty string identity field; duplicate/missing identities are rejected. Keyed arrays merge fields by identity, retain base order then new local/remote IDs, and explicitly ignore reorder-only changes. Other arrays stay atomic. Deletion remains distinct from null and resolved deletions no longer become unserializable copied sentinels. Reports contain source values and remain local simulations, not production synchronization engines.

python -m pip install .
sync-conflict-lab examples/base.json examples/local.json examples/remote.json
sync-conflict-lab examples/base.json examples/local.json examples/remote.json --strategy prefer-local --format json --output result.json

Exit code 1 means manual conflicts remain unresolved, 0 means the selected policy produced a complete simulated result, and 2 means the inputs or command were invalid. Existing reports are never overwritten.