chore(release): prepare 0.4.11-b

[ZhuchkaTriplesix]

Summary

• pubspec.yaml → 0.4.11-b
• CHANGELOG [0.4.11-b]: security + packaging (from mistagged 0.4.11-a) + perf (perf: bound peak memory & hot-path algorithms (post-0.4.11 audit) #414) + UI (ui: stuck loaders, blank states & dialog Escape (post-0.4.11 audit) #445) + code-review (code review: correctness follow-ups post #414/#445 (dev vs main) #463)
• Documents that tag 0.4.11-a pointed at the same commit as 0.4.11
• Roadmap + AUR pkgver=0.4.11-b

After merge to dev

Open dev → main release PR, then tag on the merge commit:

git checkout main && git pull
# confirm pubspec is 0.4.11-b on the tip you tag
git tag -a 0.4.11-b -m "Querya Desktop 0.4.11-b"
git push origin 0.4.11-b

Verify git rev-parse 0.4.11-b^{} ≠ 0.4.11^{} and artifacts are named Querya-Desktop-0.4.11-b-* (incl. .rpm / .flatpak).

[ZhuchkaTriplesix]

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