Expand far clipping distance when fitting large models

Large models can extend beyond the default far plane after fitting,
leaving the view blank or clipped. Pass an explicit adjustment flag
through view, model, and camera fitting, and reuse the fitted bounds
to expand clipping with a margin, rounded up to multiples of 10,000.

Adjust restored ordinary cameras after applying their saved state.
Preserve named cameras and explicit command-line clipping planes,
and avoid recalculating clipping during redraws or navigation.

Route output fitting through the view and move the bounds policy
definition out of the precompiled header.

docs/asset-loading.md

@@ -27,6 +27,25 @@ the visible step. The spinner hides immediately when work settles; there is no
 until the project's failures disappear or the project changes.
 
 Views redraw and update bounds as results arrive, but keep the user's camera.
+Interactive and output camera fits go through `lcView::ZoomExtents()`, with
+fallback geometry included for interactive views and only available geometry
+included for outputs. The view delegates fitting and saved camera undo history
+to `lcModel::ZoomExtents()`. `lcView::ZoomExtentsAtStep()` restores the model's
+current step after fitting.
+The adjustment flag passes through view, model, and camera. The camera adjusts
+clipping after updating its fitted position, using the fit's transformed bounding
+points without collecting bounds again.
+The view fit entry points take an explicit `AdjustFarPlane` flag. Initial view
+and preview fits and automatic image output fits enable it, using the bounds
+available at that time; ordinary fits disable it. The distance expands only when
+those bounds extend beyond both the default 50,000 and the current distance. Later asset
+updates, redraws, navigation, and fits do not adjust clipping again.
+Increases include a 10% margin and round up to multiples of 10,000; they never
+shrink the distance or change saved model cameras. Explicit command-line clipping
+planes remain authoritative for image output.
+Restored tab layouts defer clipping adjustment until the ordinary camera's saved
+position and settings have been applied, so a saved distance cannot undo the
+load-time expansion. Named model cameras retain their saved clipping settings.
 During synth edits, the previous generated mesh stays visible until a replacement
 settles. Images and geometry exports wait for their requirements and omit failed
 geometry instead of saving loading cubes. See [Caller policies](#caller-policies)
@@ -355,8 +374,8 @@ including current synth generations, and repeats picking before placement. If
 loading fails, both dragging and insertion use the available or fallback
 geometry rather than rejecting placement.
 
-Automatic output fitting uses `lcGeometryBoundsMode::AvailableGeometryOnly`;
-interactive fitting uses `IncludeFallbackGeometry`. A whole-model wait can
+Automatic output fitting uses `lcGeometryBoundsMode::AvailableOnly`;
+interactive fitting uses `IncludeFallback`. A whole-model wait can
 conservatively include later steps even when output requests an earlier step.
 Scene flags preventing fallback cubes do not themselves initiate a wait or
 guarantee success. See [lc_view.cpp](../common/lc_view.cpp) and