Revert of "Undo build button grid icons" (614dda8): restore the per-building
SVG icons, the QtSvg-based icon loading in BuildButtonGrid, the icon dir
plumbing in MainWindow, and the Qt5::Svg dependency.
This returns the unlock-groups branch to having the icons. The preceding
undo commit exists only so the Demolish -> Deconstruct rename can be
cherry-picked on its own (rename+icons commit together with the undo).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y7N59FsLA5e2kuVdqe4Uhc
Remove the per-building SVG icons and all their wiring (the icon assets,
the QtSvg-based icon loading in BuildButtonGrid, the icon dir plumbing in
MainWindow, and the Qt5::Svg dependency), leaving only the Demolish ->
Deconstruct rename from the previous commit.
This is the inverse of the icon half of the previous commit, paired with a
following revert that re-adds the icons. Cherry-picking the previous
"rename + icons" commit together with this undo reconstructs the rename on
its own.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y7N59FsLA5e2kuVdqe4Uhc
