Mid-April Improvements

A round of reliability and correctness improvements across the platform:

• Appointments list: loads when filter conditions return an empty result set.
• Comment attachments: the comment input stays open when you click the attachment button in feed posts.
• Chat message ordering: messages in live chat streams arrive in the order they were sent.
• Offer duplication: duplicated offers set copied prices to inactive, so a copy doesn’t create live pricing conflicts.
• Subgroup membership: removing a member from a parent group also removes them from its subgroups.
• Number inputs in worksheets: comma-formatted numbers are sanitized, so calculations work in locales that use commas as decimal or thousands separators.
• Check-in locale formatting: dates and numbers in check-in responses follow the participant’s locale.
• Check-in file uploads: file types are validated on the server, and unsupported formats are rejected before they reach storage.
• HTML embed shortcodes: shortcode values with special characters render safely in embed blocks.
• File uploads: filenames with special characters are normalized on upload, keeping media links on the CDN intact.
• Private browsing and embedded views: improved handling when the platform runs in private browsing mode or loads inside an iframe.
• Profile locale settings: users with region-specific locales that include script subtags (e.g. zh-Hant-TW) can save their profile.
• Check-in trend charts: trend graph tooltips render unit labels that contain special characters.