wip(assembler): M3 round 1 -- native FloatingIslands recipe in Core (standalone)

Bounds 517 boxes, 0 missed, negative control caught; capsule route 1044 centers, raised-route control
fails; W1/W8/W16 stable (field bf3ce7da876431e2); 39 ms native vs 64 ms legacy. My review: islands read
as thin flat pads with a radial pinch under them, not rock; next round fixes the look.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Standalone/Core/API.md

@@ -144,6 +144,26 @@ at each swept center. Automatic changes must be composed first and pass this aud
 accepted. Player carve/fill edits remain unrestricted. This validates analytic field collision and
 support; it does not cook an Unreal physics mesh.
 
+## Floating-island feature family v1 (standalone Core)
+
+`FloatingIslandRecipeV1` and `FloatingIslandManifestV1` define a separate, reusable finite 3D feature
+family. Coordinates, dimensions, and density values use signed 1/256-voxel units; negative density
+is solid. The recipe carries its seed, fixed vertical layout, site density, island count and spacing,
+radius range, top flattening, taper, bounded contour warp, roughness, blend, connector dimensions and
+route constraints. `PlanFloatingIslandCluster` emits stable island and connector IDs, a connected
+cluster graph, conservative influence AABBs, and a centerline route. At least the primary chain is
+always planned; `islandDensityQ16` controls up to two optional side sites. Connectors carry a sharp-tag
+ready bit for a later hybrid-mesher adapter.
+
+`FloatingIslandFieldV1::densitySubvoxels` evaluates the canonical island and connector field.
+`interval` returns unknown for boxes overlapping any influence AABB and a certified all-air range
+outside them. AABBs include contour displacement, roughness, taper height and smoothing reach.
+`AuditFloatingIslandBounds` checks sampled boxes and void beside connectors and includes a deliberately
+shrunken island-bound negative control. `AuditFloatingIslandRoute` samples the player capsule and
+support along the serialized route. The current field block is not yet composed into
+`WorldAssemblyManifest` or the Unreal adapter; M3 round 1 proves the standalone Core representation.
+The frozen owner evaluator is used as a visual and timing oracle, not as a hash target.
+
 ## Queries and tiles
 
 `densityAt(position)` returns signed density; negative is solid and nonnegative is air. Server and