An allocation of 4*rows pointers is a bit big for the stack if we have
16k rows.

That was probably never a good idea, but it broke GnmColor and thus
GnmBorder equality.

Newer introspection compiler is picky.

This fixes criticals for conditional formats creating dynamic deps.

When expanding a sheet, fill in the new areas with most common styles
for the rows to the left of the new columns or the columns above
the new area.

Harmless.

Add fast pre-optimization to bring down the number of entries before
we start messing with hashes.  Fixes #699045.

When we collect ranges with validation we also get input message areas.

I don't think there could be any that this point, but be safe.

This commit basically turns things on.  The meat was in the previous
long commit sequence.  GNM_DEBUG=style-deps shows the action.