## Description Follow-up from [#586921](https://gitlab.com/gitlab-org/gitlab/-/work_items/586921#note_3023890346) to implement the `DS_PIP_MANIFEST_FILE_NAME_PATTERN` flag for pip manifest file discovery. Use this new variable as a replacement for the deprecated variable `PIP_REQUIREMENTS_FILE` used in gemnasium. Although, let's maintain it for backward compatibility. ## Context The team decided to go with **Option 2** from the discussion: introduce a new flag (`DS_PIP_MANIFEST_FILE_NAME_PATTERN`) to provide explicit control over pip manifest file discovery patterns, separate from the existing `DS_PIPCOMPILE_REQUIREMENTS_FILE_NAME_PATTERN` flag used for pip-compile lock files. This allows users to: - Set different patterns for manifest files vs. lock files - Support custom manifest file naming conventions (e.g., `requirements-*.txt`) - Maintain backward compatibility with existing configurations ## Acceptance Criteria - [ ] `DS_PIP_MANIFEST_FILE_NAME_PATTERN` flag is implemented in - [ ] service (DR job) - [ ] analyzer (DS job) - [ ] Flag is properly documented - [ ] v2 template is updated to include the new flag - [ ] Tests cover custom manifest file patterns - [ ] Migration guide is updated if needed ## Related Issues - Parent: [#586921](https://gitlab.com/gitlab-org/gitlab/-/work_items/586921) - DS analyzer: Python support - Manifest scanning: requirements.txt scanning - Discussion: [Note #3023890346](https://gitlab.com/gitlab-org/gitlab/-/work_items/586921#note_3023890346)