Task D.7.4 CSV Preview Validation Engine

Date: 2026-07-02 Status: implemented

Scope Delivered

Accepts one or more CSV files through multipart/form-data.
Detects templates by filename from setup/templates/templates.json.
Treats templates.json plus checked-in CSV headers as runtime template truth.
Rejects unknown and unsupported templates with structured row/file errors.
Validates exact header names, order, duplicate columns, missing columns, and extra columns.
Parses UTF-8 comma-delimited CSV with quoted cell support.
Reports invalid encoding, empty rows, duplicate rows, inconsistent column counts, required fields, emails, booleans, integers, decimals, dates, enums, JSON metadata, format rules, and amount/line-total warnings.
Resolves dependencies from both uploaded batch files and existing database rows without writing.
Detects duplicate business keys inside each uploaded file.
Classifies rows as create, update, or error.
Returns structured file/row report with PASS, WARNING, FAIL status and previewHash for D.7.5.

No database insert/update/delete logic added.
No seed execution added.
No reset/reseed behavior added.
No document number generation, approval triggering, PDF generation, or storage writes added.
Relationship checks use read-only Drizzle selects.
quotation-topic-items.csv resolves topic_key from the uploaded batch because topic_key is an import-only alias and is not persisted in crm_quotation_topics.

npm run typecheck: passed.
npx oxlint src/features/setup/server/csv src/features/setup/server/csv-preview.service.ts src/app/api/setup/import/preview: passed.