Align testing guide filters with real tests

[silentgeckoaudit3801]

Fixes #351.

Updates TESTING_GUIDE.md so the Test Categories section uses filters that match the tests currently present in the repository:

• lifecycle scenarios: test_full_lifecycle_success and test_full_lifecycle_failure_redirection
• amount validation: prop_amount_in_range and edge_amount
• timestamp validation: prop_create_vault, prop_duration_boundary, prop_past_start_rejected, and edge timestamp filters
• create-vault integration: target-level cargo test --test create_vault

Validation: static repository/API inspection only; no project toolchain commands were run from this environment.

[1nonlypiece]

@silentgeckoaudit3801 this PR needs to be linked to an issue you're actually assigned to before it can be merged through the campaign — closing for now, happy to take another look once that's in place.