Package relocation: make package structure real and acyclic

Package relocation: make package structure real and acyclic

Moved (git mv, move-only, no behavior change):
- gui -> renderer.raster: RenderingContext, SegmentRenderingContext,
  HiZPyramid, CullingStatistics, StereoEye, Frustum, Vertex (math)
- gui -> diag: ThreadActivityRecorder, DebugLogBuffer
- gui -> geometry: Camera (decoupled from gui.FrameListener: dead
  ViewPanel param dropped, panel registers a lambda adapter)
- geometry -> renderer.raster.shapes.composite.base: Plane, BspTree,
  PolygonType (CSG machinery, used only by shapes)
- renderer.octree -> geometry: IntegerPoint (zero-dep coordinate type)
- ShapeCollection's ViewPanel overloads deleted (trivial delegates;
  callers pass getCamera()); RenderingContext.bufferedImage made public
  (AWT shell blits it); javadoc {@link}s re-qualified.

Resulting layering: math <- geometry <- renderer.raster <- gui, with
diag a standalone leaf. Remaining known renderer->gui edges (next
refactor): DeveloperTools field + mouse-picking API types
(MouseEvent/MouseInteractionController/ViewSpaceTracker/TextPointer)
and demo-only RayTracer->ViewPanel.

Verified: engine 37/37 tests, all 3 consumer repos (demos, aukio,
aukio-environment-fo4) compile, demo goldens bit-identical to the
pre-relocation run.