release: Floatick v0.2.0

[lucaslus]

Summary

Promote the tested Floatick v0.2.0 candidate into main without rebuilding the accepted package.

What is new

• Introduces Sticky Boards as lightweight virtual groups with colored previews, desktop pinning, dynamic placement, drag and resize support, and read-only task presentation.
• Adds structured todos with a title, Markdown content, details view, double-click access, and a unified bottom-drawer editing flow.
• Adds colored tag management, todo assignment, and multi-select tag filtering.
• Refines the compact main panel with dedicated archive access, a smaller new-todo action, stable floating-icon anchoring, improved first-open animation, and reliable text input.
• Adds system/light/dark appearance, Chinese/English language selection, always-on-top control, Open at Login, and Sparkle update settings.
• Adds first-run welcome todos and tags so new users can immediately explore completion, details, and filtering.
• Improves macOS packaging, universal architecture handling, unsigned candidate signatures, app icons, and window transparency/geometry.
• Adds real-engine macOS UI automation, AppKit accessibility boundary tests, isolated first-run release smoke tests, CI integration, and testing documentation.

Verification

• Candidate Draft: candidate/v0.2.0
• Accepted candidate commit: eb5cf8a60074bf1539662f842a0d6b317931b4c3
• Universal DMG, checksum, and manifest are present in the private Draft Release.
• macOS integration journeys, AppKit native tests, focused Widget tests, formatting, analysis, architecture verification, and isolated launch smoke test passed.

Release handling

Merge with a merge commit. Do not squash or rebase: the tested candidate commit must remain reachable from main before tagging it as v0.2.0.