#140 feat(import): add ywriter 7 (.yw7) import support

[Anonymous]

Originally created by: smith-and-web

Summary

• Add comprehensive yWriter 7 (.yw7) file import support for users migrating from yWriter
• Parse chapters, scenes, characters, locations with full metadata and references
• Support Parts (chapters marked with <SectionStart>) displayed distinctively in sidebar with BookOpen icon
• Convert yWriter markup ([b], [i]) and character/location descriptions to HTML for proper rendering

Changes

• New src-tauri/src/parsers/ywriter.rs with complete yWriter XML parsing
• Add is_part field to Chapter model with database migration for Parts/Chapters hierarchy
• Update Sidebar.svelte to display Parts with accent color, uppercase, and distinctive styling
• Add 3 test fixtures: hal_spacejock.yw7 (official sample), hamlet.yw7, parts_example.yw7
• 175 Rust tests, 72 frontend tests passing

Test plan

• [x] Import hal_spacejock.yw7 sample file successfully
• [x] Verify Parts display distinctively in sidebar (BookOpen icon, accent color, uppercase)
• [x] Verify character descriptions render HTML correctly (Bio/Goals as bold labels)
• [x] Verify location descriptions with "Also known as" render properly
• [x] Run full test suite (247 tests passing)

Closes [#123]

🤖 Generated with Claude Code

[Anonymous]

Ticket changed by: smith-and-web

• status: open --> closed