icsExport: Add IANA timezone support for calendar events

[Kingsman-99]

Description

icsExport generates .ics calendar files for payment due dates but writes all times in UTC without a TZID property, causing events to appear at the wrong local time in many calendar apps. Contributors should add a timezone parameter (IANA tz string) and embed the correct DTSTART;TZID=... and VTIMEZONE component in the generated ICS data.

Acceptance Criteria

• A timezone parameter (IANA string, e.g. "America/New_York") is accepted by the export function
• Generated events include DTSTART;TZID=<tz> and a VTIMEZONE block for the given timezone
• When timezone is omitted the export falls back to UTC (current behaviour)
• Existing tests continue to pass

Context

• Target file: src/lib/icsExport.ts
• Date helpers: src/lib/dateUtils.ts

[damiedee96]

Hello Maintainer, I'd love to work on this issue.

[rupesh-kumar-sah]

Hello! I'd like to work on this issue.

I can tackle icsExport: Add IANA timezone support for calendar events. Proposed implementation roadmap:

• Analysis: Inspect current behavior and edge cases in Stellar-split/split-app
• Core Implementation: Deliver a clean, modular solution for icsExport: Add IANA timezone support for calendar events strictly following Stellar-split/split-app conventions.
• Quality Assurance: Cover changes with automated tests ensuring CI passes smoothly.

Looking forward to contributing—please feel free to assign!

[macbrown27]

@macbrown27 has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Hello, I investigated the affected area and understand how the requested change should work. I'd be happy to implement it and cover the important edge cases through testing.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @macbrown27 to this issue.

[Onomebello]

@Onomebello has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

please assign me this issues

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Onomebello to this issue.

[drips-wave]

Congratulations, @Onomebello! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on September 30, 2026.

🧑‍💻 @Onomebello: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[grantfox-oss]

🦊 GrantFox — @Onomebello has been assigned to this issue!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #703)
2. Your PR will be reviewed by the Stellar-split maintainers

Good luck! Track your progress on GrantFox.