Regional mesh: per-domain IR drop

A harder power grid job: this block has three power regions with different needs. The centre core is hot and voltage-sensitive (high current, a tight IR (current times resistance) drop budget); the logic region draws little power but is packed with signals; the accel sits in between. Each region shows its current multiplier and its own budget.

Set a mesh density per region (plus the global ring). One uniform setting cannot win:

• Each region under its own IR-drop budget - the hot core needs a dense local mesh to hold its tight budget; the cooler regions need far less.
• Signal routing closes in every region - a dense mesh steals tracks, and the routing-heavy logic region cannot take a heavy mesh. Crank density everywhere and its routing fails. Run Place & Route to check each region.

Widen the ring to lift every region at once, then give each region only the density it needs: heavy on the core, light on logic. Place & Route, then Submit design.