Describe the feature

a way to increase explosion resistance of the current camo'd frame, maybe with obsidian?

Framed Blocks currently copy the explosion resistance from the applied camo.
Applying some kind of "obsidian reinforcement" would be a good option to increase the explosion resistance and durability, I just need a good way to visualize it (at least on the bare frame). I'll look into adding this

obsidian in the offhand with a tool in main hand to apply?

I would prefer a dedicated item for two reasons:

1. Placing a block in the off-hand already has a another functionality in FramedBlocks: immediately applying that block as a camo
2. If I'm adding a new tool anyway (adding that functionality to existing tools would be bad for discoverability and usability), then I might as well just make a dedicated reinforcement item

The main issue for now is the visualisation though, the rest is fairly straightforward.

The implementation I went for is pretty simplistic: the reinforcement provides the block with obsidian-level explosition resistance and can be removed by right clicking with any pickaxe-type tool that can break obsidian blocks. The status is indicated by showing a HUD when looking at a block with the reinforcement item in the main hand.