refactor: Rename root_is_on_right to sibling_is_on_right for clarity

[zlangley]

Renames the variable root_is_on_right to sibling_is_on_right throughout the codebase to better reflect its meaning. The field represents whether the sibling in the Merkle tree is on the right, not the root.

[github-actions]

group	app.proof_time_ms	app.cycles	app.cells_used	leaf.proof_time_ms	leaf.cycles	leaf.cells_used
verify_fibair	(+22 [+1.6%]) 1,410	147,020	8,194,664	-	-	-
fibonacci_program	(+49 [+1.0%]) 5,017	1,500,096	51,485,167	-	-	-
regex_program	(-65 [-0.5%]) 13,826	4,140,164	167,389,450	-	-	-
ecrecover_program	(+62 [+2.5%]) 2,558	295,181	15,586,346	-	-	-

Commit: 958d937

Benchmark Workflow

[vercel]

Deployment failed with the following error:

Creating the Deployment Timed Out.