Example booking workflow: route decision conditions on the result element (validation.result)

The example booking workflow's operator-decision flows compare the bare result variable against a scalar (validation == approved), but a comment/review task stores its outcome as a structured {result, comment} value, so the outcome lives under result. The orchestra example workflows use the dotted form (decision.result); this workflow should follow the same convention.

Seven conditions are affected: n_validate (validation), n_refund_review (refund_review) and n_attendance (attendance), which now read validation.result, refund_review.result and attendance.result.

Note: orchestra now resolves a bare result variable to its result element too (a comment/review outcome routes the same whether you write the variable or its .result path), so this is not a functional break, it aligns the example with the documented convention and reads clearly.