[1sakshm]

Description

DELETE /templates/{id} always deleted the template's PDF from disk, even when it was still needed:

• The bundled seed PDF: deleting the seeded "Manual Test Template" deleted data/inputs/file_template_manual.pdf, a file tracked in the repo. If the template table was later empty, seed_db() re-created the template on the next start, pointing at a PDF that no longer existed.
• A PDF shared by several templates: POST /templates/create accepts any existing pdf_path, so two templates can point at the same file. Deleting one broke the other.

Changes:

• app/core/config.py: new SEED_TEMPLATE_PDF_PATH constant, now used by seed_db() instead of the hard-coded string.
• app/services/template.py: delete_template only unlinks the PDF if _pdf_still_needed() is false. It is "still needed" when it's the seed PDF, or when another template resolves to the same file. Paths are compared after resolving, so data/inputs/x.pdf and ./data/inputs/x.pdf count as the same file.

Everything else about deletion is unchanged: submissions, their output PDFs, and jobs are still removed, and a PDF used only by the deleted template is still deleted (the existing test_delete_template_deletes_pdf_file still passes).

Fixes #738

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Added two tests in tests/test_deletion.py:
  • test_delete_template_keeps_pdf_shared_with_another_template: two templates share a PDF; deleting the first keeps the file, deleting the second removes it
  • test_delete_template_keeps_seed_pdf: deleting a template that uses the seed PDF keeps the file
  • Both fail on development and pass with this change
• Full suite: python -m pytest tests/ → 315 passed
• ruff check app/ → all checks passed

Test Configuration:

• Python version: 3.11
• Docker/Compose version: N/A (tests run locally)
• OS: Windows 11

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• The Lint workflow check passes on this PR ✅
• The Tests workflow check passes on this PR ✅