feat: add employee group proto definitions with CRUD, list, and import/export capabilities

[ilramdhan]

Description

This pull request introduces a new EmployeeGroup master data model and associated CRUD and batch import/export API definitions to the IAM service. The changes add a new protobuf file, employee_group.proto, which defines the EmployeeGroup entity, request/response messages for all operations, and the EmployeeGroupService with RESTful HTTP bindings.

Change Type

• ✨ New service/message
• ➕ Add field/RPC/enum value
• 🔄 Modify validation
• 📝 Documentation update
• ⚠️ Deprecation
• 🔧 Config/script changes

Proto Files Changed

• iam/v1/employee_group.proto

Changes Made

The most important changes are:

New Entity and Core CRUD API:

• Added the EmployeeGroup message, representing a department or functional group (e.g., ASM, DYM, MGR), with fields for ID, code, name, active status, and audit info.
• Defined create, get, update (code is immutable), and delete (soft delete) request/response messages and corresponding RPCs in the new EmployeeGroupService.

Listing, Search, and Filtering:

• Added paginated listing with search, active status filtering, and sorting (by code, name, or created_at) via the ListEmployeeGroupsRequest and ListEmployeeGroupsResponse messages and RPC.

Excel Import/Export and Template Download:

• Added support for exporting employee groups to Excel, importing from Excel with duplicate handling, and downloading an import template, each with dedicated request/response messages and service methods.

Validation and Metadata:

Breaking Change Check

Is this a breaking change?

• No - buf breaking passes
• Yes - Requires version bump

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Pre-merge Checklist

• I have read and followed RULES.md
• buf format -w applied
• buf lint passes
• buf breaking passes
• Comments document new messages/fields
• REST mappings follow conventions
• Validation rules are complete
• Field numbers are logical

Impact Assessment

• Backend code regeneration required
• Frontend code regeneration required
• OpenAPI spec regeneration required

[Copilot]

Pull request overview

Adds a new IAM master-data protobuf definition for EmployeeGroup, including a REST-mapped gRPC service for CRUD, listing (search/filter/sort/pagination), and Excel import/export/template download—mirroring existing IAM master-data patterns (e.g., EmployeeLevel).

Changes:

• Introduce EmployeeGroup entity message with audit metadata.
• Add request/response messages for create/get/update/delete and list operations.
• Add Excel export/import and template download messages + EmployeeGroupService HTTP bindings.

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[Copilot]

UpdateEmployeeGroupRequest.name is documented as "1-100 chars if provided", but the validation only enforces max_len: 100 (so an explicit empty string would be accepted). Either enforce min_len: 1 when set, or adjust the comment to reflect that an empty string is allowed (e.g., to clear the name).

Suggested change

	optional string name = 2 [(buf.validate.field).string = {max_len: 100}];
	optional string name = 2 [(buf.validate.field).string = {
	min_len: 1
	max_len: 100
	}];