Issue 1314 — tcEdit: per-step execution type + step-manager commands restored

The modern Test Case Editor regains the legacy per-step editor capabilities: per-step execution type and the step-manager commands Insert, Copy, Move Up/Down, Resequence, plus the duplicate step-number guard.

Legacy (1.9.20)

Per-step Select exec type shown only when the project option automationEnabled is ON; toolbar insert/copy/reorder/resequence/delete; duplicate step numbers rejected with warning_step_number_already_exists.

Modern (2.0.1)

• BFF api/testcasesedit/index.php: edit payload carries automation_enabled; update accepts per-step execution_type → testcase::create_step validates against {1 Manual, 2 Automated} (3/4 normalized to Manual, as legacy).
• gui/templates/testcases/tcEdit.html: per-row .step-exect select (gated on the project flag), per-row Insert/Copy/MoveUp/MoveDown/Delete, header Resequence; collectSteps() reads per-row types; doSave() validates step numbers (duplicate/blank → localized warning).
• i18n: 8 new tcedit.* keys in all 10 bundles.

Verification

• Browser: renders correctly; Insert/Copy/Move/Resequence work; automated-step exec type survives Save (pre-fix runs measured the 2->1 wipe).
• BFF round-trip: reordered set (automated/ex2 first) saved as step1 automated/2, step2 manual/1, step3 inserted/1 — verified via SQL.
• Test suite tmp/TLU_Test_Cases.md #1314: 8/8 PASS. (Refs #1314)