Make free-standing 3D-printed text one connected solid

When turning words into a free-standing 3D print (no plaque), separate glyphs are floating islands that fall off the bed. Fix: build a white underlay = offset(r=halo) of the text, which fattens each letter until neighbors fuse into one solid; overlap multi-line text and tighten letter spacing (spacing<1) to bond words vertically. The black front face is a shallow linear_extrude of the plain text subtracted into the top of that body, so export white+black as separate origin-shared STLs for AMS. Verify it is truly ONE piece by exporting the STL and running union-find over rounded shared vertices to count connected components (want 1) before trusting it.