v1.9.0: First-run examples and clear all

The start-with-an-example release.

Added

• Start with an example: first visits begin with an empty table and a panel of 8 preset rolls, each card showing its real engine-computed average and range. "Use this roll" adds one, "Load every example" adds all 8, and "Start from a blank roll" works like Add roll. Deleting or clearing every roll returns to the panel.
• Examples dialog: once the table has rows, the same preset cards stay reachable from an Examples toolbar button. Adding one appends it to the table, and re-adding an example renames the copy, like "Weapon attack (2)".
• Clear all: a red button next to Add roll that empties the table after a confirmation dialog. Clearing also unpins the baseline. On phones the button reads "Clear".
• Quickstart: step 1 now mentions the example panel and the Examples button.

Changed

• Every Add roll button now disables at the 100-roll cap with an explanatory tooltip, including the one in the toolbar.

Full notes in the CHANGELOG.