docs: limit iterations in consensus_tree() example for fast execution

[Copilot]

The consensus_tree() example used the default num.samples = 10000, causing slow execution during R CMD check (~several seconds).

Changes:

• Set num.samples = 100 in the example
• Example now runs in ~0.2 seconds (verified under 1 second requirement)
• Regenerated documentation with devtools::document()

## The consensus tree for it
consensus_tree(g, hrg = hrg, start = TRUE, num.samples = 100)

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