feat(frontend): chunked routing import + fix route_sequences key column

[ilramdhan]

• SheetGroupConfig.keyColumn override: each sheet group can specify its own key column; worker uses groupCfg.keyColumn ?? msg.keyColumn
• BULK_ROUTING_CONFIG: route_sequences and route_rms now use "route_head_legacy_product_id" (the actual column name in the Excel export) instead of the incorrect "route_head_legacy_id"
• BulkImportDialog: adds chunked import path (parsing → ready → chunked_importing → chunked_done/failed) alongside the existing validate flow; files > 5 MB only show Chunked Import button

Description

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 🎨 UI/UX improvement
• ♻️ Refactor
• 📚 Documentation
• 🔧 Chore (deps, config)

Module/Component Affected

• Dashboard
• Finance
• HR / IT / CI / EXSIM
• Components (common/)
• Components (ui/)
• Navigation
• API Routes

Changes Made

Related Issues

Fixes #
Related to #

Screenshots

Before

After

Testing Performed

Manual Testing

• Desktop (1440px+)
• Tablet (768px)
• Mobile (375px)
• Light mode
• Dark mode

Browser Testing

• Chrome
• Firefox
• Safari
• Edge

Build Verification

• npm run lint passes
• npx tsc --noEmit passes
• npm run build succeeds

Accessibility

• Keyboard navigation works
• Screen reader compatible
• Proper ARIA labels
• Color contrast adequate

Performance

• No unnecessary re-renders
• Images optimized
• Heavy components lazy loaded

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Pre-merge Checklist

• I have read and followed RULES.md
• I have read and followed CONTRIBUTING.md
• Loading states implemented (if data fetching)
• Error handling present
• Component props typed properly
• Uses semantic color classes
• Responsive design tested
• Dark mode compatible
• Screenshots included (for UI changes)

Reviewer Notes