Feat/handle decimal chapters

[EliasLd]

Add support for decimal chapters and improve range selection

Summary

This PR introduces generic support for decimal chapter numbers and chapter 0 across goweeb's existing providers, improves chapter range selection, and updates the TUI to display long lists of available chapters more clearly.

Changes

Generic chapter numbering

• Introduce a shared ChapterNumber type in internal/source/common.
• Support integer and decimal chapter numbers without floating-point precision issues.
• Normalize chapter numbers, preserving values such as 0, 3.5 and 14.25.
• Update chapter sorting, deduplication and range filtering to use numeric comparisons.
• Preserve decimal chapter numbers in PDF filenames, temporary directories and ebook-friendly folders.

Provider integration

• Update Anime-Sama, MangaDex, Mangavyvy, WeebCentral and MangaFreak to support decimal chapter numbers.
• Replace integer-only parsing with the shared chapter number parser.
• Stop skipping decimal chapters such as 3.5 and 14.5.
• Preserve provider-specific chapter URLs and existing download behavior.

Chapter range selection

• Extend range parsing to support decimal chapter numbers and chapter 0.
• Support selections such as 0, 3.5, 1-6.5 and 1-6,6.5,7-10.
• Include decimal chapters when selecting a range that contains them.
• Preserve existing multi-range and last-N chapter selection behavior.
• Display decimal chapters separately between consecutive integer ranges.

TUI improvements

• Automatically wrap long lists of available chapters according to the terminal width.
• Keep individual chapter ranges intact when wrapping.
• Display all available ranges across multiple lines without truncation.
• Preserve the existing range selection workflow and layout.

Notes

• Decimal chapters are now supported throughout the discovery, selection and download workflow.
• MangaDex titles that restart chapter numbering for each volume remain unsupported.
• Chapters without a numeric identifier require separate handling.