Document Matching UI

Surface document matches on the detail page so users can navigate between matched documents (e.g., invoice ↔ contract).

Requirements

• New "Matches" tab in section tabs, with a collapsible section at the top of the content area
• Tab only appears when matches exist for the document
• Minimal match card: document type badge + display name/number + link to view
• All document types (invoice, contract, PO, GRN)

Data Flow

1. DB query (db.document-matching/get-matches-for-document): Join document_match with document to return matched documents with type, id, and structured-data (for display name extraction). Handle canonical ordering (a < b) by querying both sides.

2. Handler (view/get-document): Call the matches query, pass results as :matches in opts to the renderer.

3. Tabs (shared/section-tabs-for-type): Accept matches parameter. Append "Matches" tab when (seq matches).

4. Section (shared/matches-section): Render at the top of the type-specific view. Each match is a card with type badge, display name, and link.

Match Card

┌─────────────────────────────────────────┐
│  [Contract]  Service Agreement 2025     │
│              ↗ View document            │
└─────────────────────────────────────────┘

• Type badge reuses existing badge-{type} CSS classes
• Display name extracted from structured-data per type (contract title/number, PO number, invoice number, etc.)
• Link navigates to matched document's detail page

Display Name Extraction

Per document type:

• Invoice: invoice-number, fallback to issuer name
• Contract: title or contract-number
• Purchase Order: po-number
• Goods Received Note: grn-number
• Financial Notice: notice-type + sender name

Files to Modify

1. src/com/getorcha/db/document_matching.clj — add/modify query
2. src/com/getorcha/erp/http/documents/view.clj — handler fetches matches
3. src/com/getorcha/erp/http/documents/view/shared.clj — tabs + matches section rendering