feat: refine announcement

[syuilo]

What

#11328

Why

Resolve #11328

Additional info (optional)

• 既読お知らせのクライアント側キャッシュ
• deactivateされたお知らせタブ
• テスト
• メール通知？

Checklist

• Read the contribution guide
• Test working in a local environment
• (If needed) Add story of storybook
• (If needed) Update CHANGELOG.md
• (If possible) Add tests

[codecov]

Codecov Report

Merging #11497 (c8300bf) into develop (dc8a130) will increase coverage by 0.04%.
Report is 13 commits behind head on develop.
The diff coverage is 81.68%.

@@             Coverage Diff             @@
##           develop   #11497      +/-   ##
===========================================
+ Coverage    78.63%   78.68%   +0.04%     
===========================================
  Files          920      922       +2     
  Lines        97492    97688     +196     
  Branches      7704     7725      +21     
===========================================
+ Hits         76659    76861     +202     
+ Misses       20833    20827       -6     

Files Changed	Coverage Δ
packages/backend/src/server/api/stream/types.ts	0.00% <0.00%> (ø)
packages/frontend/src/account.ts	13.96% <0.00%> (+0.04%)	⬆️
packages/frontend/src/components/MkNoteHeader.vue	100.00% <ø> (ø)
packages/frontend/src/components/MkNoteSimple.vue	100.00% <ø> (ø)
...c/server/api/endpoints/admin/announcements/list.ts	72.72% <8.33%> (-7.09%)	⬇️
.../backend/src/server/api/endpoints/announcements.ts	83.58% <41.66%> (+2.45%)	⬆️
...server/api/endpoints/admin/announcements/create.ts	83.33% <50.00%> (-3.88%)	⬇️
...server/api/endpoints/admin/announcements/update.ts	75.36% <54.54%> (-4.30%)	⬇️
...nd/src/server/api/endpoints/i/read-announcement.ts	94.87% <75.00%> (+30.91%)	⬆️
packages/backend/src/core/AnnouncementService.ts	84.44% <84.44%> (ø)
... and 6 more

... and 2 files with indirect coverage changes

[syuilo]

[syuilo]

70%くらい終わった

[syuilo]

テスト書いた

[syuilo]

マージするか