feat(settings): Schema foundation + Editor/General settings

[tomymaritano]

Summary

Implement the settings infrastructure and core settings (Editor + General).

Reference: Inkdrop settings UI

Tasks

Phase 0: Schema Foundation

• Create stores/settings/schema.ts (types + defaults + version)
• Create stores/settings/settingsStore.ts (persist + migrate)
• Export selectors for each section

Phase 1: MVP

• Build reusable components: SettingRow, Toggle, Select, NumberInput
• Implement EditorSection.tsx
• Wire editor settings to CodeMirror
• Implement GeneralSection.tsx (default notebook, open folder)
• Update sidebar with new sections

Architecture

3-layer separation:

1. Schema - Data model with versioning (SETTINGS_VERSION = 1)
2. Store - Zustand persist with migrate function
3. UI - Reusable components consuming store

Editor Settings

Setting	Type	Default
Line Numbers	checkbox	false
Highlight Active Line	checkbox	false
Line Wrapping	checkbox	true
Inline Image Widgets	checkbox	true
Scroll Past End	checkbox	true
Font Size	number	14
Font Family	text	system-ui, monospace
Line Height	number	1.6
Tab Size	number	2
Indent with Tabs	checkbox	false

General Settings

Setting	Type	Default
Default Notebook	dropdown	Inbox
Open Data Folder	button	-