Empirically the DWG \"loaded\" bit doesn't track AutoCAD's XREF Manager
\"Loaded\"/\"Unloaded\" state reliably:
- File A: manager \"Loaded\", on-disk is_loaded = Some(true)
- File B: manager \"Loaded\", on-disk is_loaded = Some(false)
Same UI state, opposite bit values, so we were incorrectly skipping
xrefs the user wants loaded. Drop the `is_loaded == Some(false)` skip
and auto-resolve every xref again. The OOM problem this was meant to
mitigate is now addressed by the frustum culler, so loading more
xrefs no longer threatens the GPU budget.
The `BlockRecord::is_loaded` field + acadrust patch stay in place so
we can revisit once we identify the actual on-disk representation of
XREF→Unload (likely an XREF dependency record or
ACAD_XREF_PANEL_DATA xrecord).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>