fix(bugs): bug tracker UX polish

[jamofer]

Summary

• Severity select in NewBugDialog now shows colored Badge pills instead of plain text
• Bug detail: severity and status editable via Select with Badge pills in context panel
• Bug detail: inline click-to-edit for bug title
• Bug detail: affected version picker added to context panel (was missing, only fixed-in existed)
• Bug list: sort by severity/creation date via new sort_by backend param + UI dropdown
• Bug list: show creator name and last update timestamp, fix DateLabel iso prop
• Public report dialog: min date prevents selecting past dates, submit validates expiration is in the future
• Context panel: consistent row alignment with fixed icon column width
• Export SEVERITIES array from bugConfig.js, refactor FixedInVersionPicker into generic VersionPicker
• i18n keys added for all 5 locales