* feat(mode): add demo mode

* chroe: Update store/db/db.go
Co-authored-by: boojack <stevenlgtm@gmail.com>

* chroe: Update store/db/db.go
Co-authored-by: boojack <stevenlgtm@gmail.com>

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Co-authored-by: boojack <stevenlgtm@gmail.com>

* feat: implement sign in with SSO

* chore: update

* chore: update

* chore: update

* feat: add SSO related UI

* chore: update

* feat: generate RSS item title and limit item count

* Update server/rss.go
Co-authored-by: boojack <stevenlgtm@gmail.com>

* Update server/rss.go

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Co-authored-by: boojack <stevenlgtm@gmail.com>

feat: add cache for idp

fix: idp definition

* feat: implement idp server

* chore: update

refactor: add `avatar_url` field to user table

* feat: introduce idp table

* chore: update

* chore: add beta badge to storage

* chore: update

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

* Update README.md

* fix typos in readme

* Update README.md

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Co-authored-by: boojack <stevenlgtm@gmail.com>

* feat(system): support for disabling public memos

* fix(web/editor): set visibility to private on disabled public memos

* feat(server/memo): find/check if public memos are disabled

* fix(server/memo): handle error for finding system error

* fix(server/memo): unmarshal visiblity when getting system settings

* chore(web): move side effect imports to end

* Update memo.go

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Co-authored-by: boojack <stevenlgtm@gmail.com>

* feat: style for not found page (#1078)

* chore: translation for not found page (#1078)

* feat: add not found page (#1078)

* chore: router for not found page (#1078)

* fix: typo

* feat: storage service backend

* update go.mod

* update the column name (urlPrefix -> url_prefix)

* update

* update

* feat: add storage service table

* update json field name

* update table name

* add updated_ts