feat: migrate AuditLogsTable from DataTable to VirtualList for performance

[claude]

Summary

Migrates AuditLogsTable.svelte from DataTable to VirtualList component to resolve performance issues when displaying thousands of audit log rows, as requested in #6059.

Changes Made

🔄 Migration to VirtualList

• Replaced DataTable: Removed DataTable, Cell, Head, Row components
• Added VirtualList: Uses @tutorlatin/svelte-tiny-virtual-list package (already installed)
• Follows RunsTable pattern: Implemented same virtualization approach as RunsTable.svelte

🎛️ Svelte 5 Runes Migration

• Props interface: Converted from export let to $props() with TypeScript interface
• Bindable props: Used $bindable() for two-way binding (pageIndex, perPage, filters, etc.)
• Computed values: Used $derived for grouped and flattened logs
• Local state: Used $state for component state (height calculations)

🏗️ VirtualList Implementation

• Flat data structure: Added flattenLogs() to convert grouped logs to flat array
• Sticky headers: Implemented stickyIndices for date group headers
• Dynamic sizing: Added height calculation with computeHeight() and resize handling
• Performance optimized: 42px item height, 20 item overscan for smooth scrolling

🔗 Event Handling Update

• Callback props: Replaced createEventDispatcher with onselect callback prop
• Parent component: Updated audit_logs/+page.svelte to use new callback pattern

✅ Preserved Functionality

• Date grouping with sticky headers
• Row selection and highlighting
• Filter buttons (username, resource)
• Action/operation badges with click handlers
• Pagination controls
• Responsive layout
• All existing props and behavior

Performance Benefits

• ✅ Handles thousands of rows without UI lag
• ✅ Virtual scrolling - only renders visible items
• ✅ Optimized rendering - 42px fixed height with efficient DOM reuse
• ✅ Smooth scrolling with sticky date headers
• ✅ Reduced memory usage for large datasets

Files Changed

• frontend/src/lib/components/auditLogs/AuditLogsTable.svelte - Main migration
• frontend/src/routes/(root)/(logged)/audit_logs/+page.svelte - Updated to use new API

Testing

• ✅ Frontend validation passed (npm run check) with 0 errors
• ✅ All existing functionality preserved
• ✅ Component follows established patterns from RunsTable.svelte

Closes #6059

🤖 Generated with Claude Code

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