[Feature]: Project Data Export & Portability (/pm project export to CSV & Markdown)

[espdesign]

Summary

Introduce /pm project export to allow server managers and project leads to export all active and archived tasks for a project as downloadable CSV, Markdown, or JSON file attachments directly in Discord.

Background & Context

Early adopters and server leads testing the bot during alpha need data ownership and portability assurance. Providing a zero-friction export command gives testers confidence that their team's project records are never locked in or trapped inside the bot database.

Proposed Capabilities

1. Slash Command (/pm project export [project] format:[csv|markdown|json] [include_archived:bool]):
   • Authorized for Server Managers and Project Leads.
   • Project name autocomplete support.
2. Multi-Format Serialization:
   • CSV: Standard columns: Short ID, Title, Status, Priority, Assignee ID, Due Date, Completed Date, Created Date, Thread Jump URL.
   • Markdown: Formatted summary table grouped by status and priority, ideal for posting to GitHub or external notes.
   • JSON: Machine-readable payload mapped to RFC 5545 and Microsoft Graph schema standards.
3. Discord File Attachment:
   • Serializes into memory (io.BytesIO) without writing temporary files to disk, and sends as a direct message attachment.

Acceptance Criteria

• /pm project export generates valid CSV, Markdown, and JSON payloads.
• Uploads export directly to Discord as a file attachment.
• Honors include_archived flag to allow full backups.
• Unit tests for exporters and permission checks.