[PortLoadView / LayerMappedView] rename/add new views

MIGRATION.md

@@ -599,17 +599,23 @@ old Nx4 form.
 `BuildReport` mapping fields are now defensively copied and read-only. Copy a
 field to a new `dict` before adding or removing report entries.
 
-`PortsLibraryView`, `OverlayLibrary`, and source-backed outputs returned by
-`LibraryBuilder.build()` borrow their sources. They do not close source resources, and
-`PortsLibraryView` is not a context manager. Keep each lazy source open and
-unchanged until every borrowing view or overlay is finished, then close the
-owning source explicitly. An eager `build(output='library')` result is detached
-and does not need its sources afterward.
+`PortLoadView`, `LayerMappedView`, `OverlayLibrary`, and source-backed outputs
+returned by `LibraryBuilder.build()` borrow their sources. They do not close
+source resources, and the views are not context managers. Keep each lazy
+source open and unchanged until every borrowing view or overlay is finished,
+then close the owning source explicitly. An eager `build(output='library')`
+result is detached and does not need its sources afterward.
 
 Lazy GDS sources no longer provide `with_ports_from_data()` or
 `with_port_overrides()` convenience methods. Construct the generic view
-directly instead: `PortsLibraryView(source, layers=...)` imports port data, and
-`PortsLibraryView(source, ports=..., replace=...)` applies explicit overrides.
+directly instead: `PortLoadView(source, layers=...)` imports port data, and
+`PortLoadView(source, ports=..., replace=...)` applies explicit overrides.
+
+`LayerMappedView(source, map_layer)` lazily remaps shape and label layers while
+leaving the source untouched. Its default `copy_through=False` forces mapped
+serialization of every cell. Set `copy_through=True` only when source-aware
+writers may copy untouched cells unchanged and intentionally skip their layer
+mapping; persistently accessed cells are mapped and no longer copied through.
 
 Generic borrowing views no longer expose GDS-specific `raw_struct_bytes()`,
 `can_copy_raw_struct()`, or forwarded `library_info` attributes. Keep the
@@ -697,11 +703,12 @@ through `source_cell()`; format writers decide whether that provenance permits
 raw copy-through. Raw GDS structure access remains confined to GDS sources and
 writers.
 
-`LibraryBuilder`, `OverlayLibrary`, and `PortsLibraryView` are new additive
-library implementations. `LibraryBuilder` supports declarative `@cell` recipes
-and dependency-aware builds; `OverlayLibrary` composes source libraries without
-eagerly copying all patterns; `PortsLibraryView` overlays port metadata on a
-read-only source.
+`LibraryBuilder`, `OverlayLibrary`, `PortLoadView`, and `LayerMappedView` are new
+additive library implementations. `LibraryBuilder` supports declarative `@cell`
+recipes and dependency-aware builds; `OverlayLibrary` composes source libraries
+without eagerly copying all patterns; `PortLoadView` loads port metadata from
+labels and/or explicit mappings; `LayerMappedView` remaps shape and label layers
+on detached materialization.
 
 Flattening with `flatten_ports=True` now rejects repeated refs whose target has
 ports, because expanding them would create duplicate port names. Resolve the
@@ -797,7 +804,7 @@ scikit-image implementation. The `arrow` and `boolean` extras are also new.
 These are additive, but available now from `masque` and `masque.builder`:
 
 - from `masque`: `RectCollection`, `boolean`, `OverlayLibrary`,
-  `PortsLibraryView`, `IMaterializable`, `IBorrowing`, `LibraryBuilder`,
+  `PortLoadView`, `LayerMappedView`, `IMaterializable`, `IBorrowing`, `LibraryBuilder`,
   `BuildReport`, `CellProvenance`, and `cell`
 - from `masque.builder`: `CostCallable`, `RenderStepKind`, the concrete
   primitive-offer classes, structured route error/status types,