release: Floatick 0.3.4 — focused todos and deadlines

[lucaslus]

Summary

• add an explicit Todo → Doing → Done flow with focused active-work filtering
• add deadlines, advance reminders, overdue state, and native in-app reminder delivery
• keep Todo and Quick Notes as the focused local-first workspace
• refresh the bilingual website Hero, SEO copy, social image, and README for the 0.3.4 workflow
• prepare the 0.3.4+11 universal macOS release

Verification

• Release Candidate workflow passed formatting, analysis, full Flutter tests, universal release build, update-feed validation, architecture checks, and launch smoke test for commit a2ca42d9c653b45280fdd34ebbc1011eb24fb3b7
• Astro production build passed
• English and Chinese desktop pages plus the 390px mobile layout passed browser QA without runtime errors or horizontal overflow
• WebGL Hero, static fallback image, and desktop hover expansion were verified

Release

• accepted candidate tag: candidate/v0.3.4
• accepted candidate commit: a2ca42d9c653b45280fdd34ebbc1011eb24fb3b7
• merge strategy: merge commit (do not squash or rebase)