fix: Re-importable Bulk Export Closure and Lookup Master Fixes

[ilramdhan]

Description

This PR significantly enhances the Bulk Export feature, ensuring that any generated Excel file is fully "re-importable" across different environments without breaking relational dependencies.

It achieves this by implementing a Breadth-First Search (BFS) closure that automatically exports the entire dependency tree of a selected product. Additionally, it transitions the universal cross-sheet key from flex_02 to product_code, ensuring stability for products created within the app rather than imported from Oracle. It also resolves a dynamic SQL issue where lookup dropdowns were returning empty results due to incorrect column name mapping.

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that changes existing API)
• ♻️ Refactor (code change without new feature or bug fix)
• 📚 Documentation update
• 🧪 Test update
• 🔧 Chore (dependencies, config, etc.)

Service(s) Affected

• Finance Service
• IAM Service
• Shared Proto (gen/)
• Root/Common

Changes Made

📤 Re-importable Bulk Export Closure

• BFS Product Closure: Added ProductSysIDs filter to ExportRequest. Added resolveProductClosure() which performs a BFS from the seed products, crawling through PRODUCT-type route RMs to collect every intermediate product in the dependency tree. The resulting export includes the full closure, guaranteeing no broken references on re-import.
• Universal Cross-Sheet Key: Switched the legacy key from flex_02 to product_code. flex_02 is empty for products created directly within the app, causing export/import failures. product_code ensures a stable, non-empty identifier.
• Cross-Reference Resolution: Fixed route_head, route_sequences, and route_rms sheets to use product_code instead of raw integer IDs (product_sys_id / head_id) so that sheet cross-references resolve correctly during import.
• Sheet/Column Alignment: Fixed template sheet names (e.g., product_parameters, product_applicable_params, route_sequences, route_rms) and added the data_type column to the product_parameters sheet to strictly match the import validator's expectations.
• Data Filtering: cpp and capp rows are now strictly filtered to only include products present in the export closure.

🐛 Bug Fixes

• Lookup Master Columns: Fixed an issue where ListMasterOptions returned empty dropdowns. Migration 000394 originally seeded lm_code_field and lm_label_field with camelCase proto fields (e.g., machineCode). This is now corrected to use actual snake_case DB column names (e.g., mc_code) for dynamic SQL mapping.
• PostgreSQL 18 Type Inference (SQLSTATE 42P08): Added an explicit $8::text cast in the BulkUpsertByLegacyID subquery to prevent type inference failures when the same parameter appears in both VALUES and a correlated subquery.

Related Issues

Fixes #
Related to #

API Changes (if applicable)

Proto Changes

// No Proto Changes

Breaking Changes

None.

Testing Performed

Unit Tests

• Existing unit tests pass
• Coverage maintained/improved

Integration Tests

• New integration tests added
• Existing integration tests pass

Manual Testing

# Deployed Finance Service locally
# Triggered Bulk Export for a single product and verified BFS closure gathered all sub-materials
# Verified the exported Excel file could be seamlessly re-imported into a clean database environment
# Verified Lookup Master dropdowns correctly populate data in the UI

Lint & Build

• golangci-lint run ./... passes
• go build ./... succeeds
• go test -race ./... passes

Database (if applicable)

• Migration added
• Migration tested (up and down)
• No breaking schema changes (or documented)

Documentation

• README.md updated (if needed)
• RULES.md updated (if needed)
• Proto comments updated
• OpenAPI regenerated

Rollback Plan

Revert the finance-service deployment to the previous stable tag. Reverting will cause exports of app-created products to use the old flex_02 key, which may not be re-importable, but will not corrupt any existing database state.

Screenshots/Logs (if applicable)

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Pre-merge Checklist

• I have read and followed RULES.md
• I have read and followed CONTRIBUTING.md
• Clean Architecture principles followed
• All errors are properly handled
• Context is passed appropriately
• Structured logging is used
• No hardcoded secrets
• PR description is complete and clear
• CI checks are passing

Reviewer Notes

• BFS Depth limits: The resolveProductClosure BFS algorithm safely collects the entire tree structure. Circular dependencies are natively avoided by tracking visited product_codes.
• SQLSTATE 42P08: The cast fix is specific to pgx/PostgreSQL 18 behavior where untyped placeholders in complex ON CONFLICT subqueries fail parser resolution.