v1.15.0

• fix parsing when Output is followed by lower-level node (see #705 reported by @Krysztophe),
• minor fixes in tests,
• fix computation of average IO speed,
• IO timings now appear in the Grid view,
• misc packages updates,
• sample plans reworked (contribution from @Krysztophe),
• improved parsing of JSON formats (ModifyTable node type, Partial Mode),
• improved parsing of Merge node type for text format,
• remove dependence on clarinet (see https://blog.dalibo.com/2025/04/29/execution-plans-invalid-json.html).