OnCall context
- move_layer/2: up/down position swap for schedule layers, mirror of
move_escalation_rule/2 (tested for both directions + boundary no-op).
ScheduleLive.Show
- New move_layer event handler.
- Up/down arrow buttons on each layer card; the top arrow is disabled on
the first layer, the bottom on the last (matches the escalation policy
level reorder UX shipped in chunk 1).
- Replaced two per-hour walks (build_layer_spans + build_final_spans -
~672 resolve calls per render at 14 days) with Resolver.resolve_range/3
+ a small segments_to_spans/3 mapper. Per-layer view wraps each layer
in a temporary single-layer %Schedule{} so the resolver code path is
shared and overrides don't bleed into the per-layer strip.
Tests: 3 new context tests for move_layer, 1 new integration test for
the layer reorder UI. Full suite 10,214 / 0 failures. Format/dialyzer
clean.
Graham McIntire
23304e108c
