v1.5.6

New features

 - Added nested FB2 <sequence> support to template metadata.
 - .Series template entries now expose .Parent, where -1 means top-level and other values point to the parent index in .Series.
 - Nested sequences are flattened in parent-then-child order for template use.
 - Updated default title_template to build compact series paths:
   - Nested sequences use the first top-level series and its first child chain.
   - Flat sequence arrays use all sequence entries.
   - The displayed number comes from the last selected sequence.
 - Updated template documentation and config comments with .Parent examples.
 - Added tests for nested and flat series title-template behavior.

Maintenance

- Moving to go1.26.5 with dependencies update

Full Changelog: v1.5.5...v1.5.6