Add ascii draw regression test for mid-trace measurements

[VaggelisGian]

Refs #5258

Test-only regression coverage for the mid-circuit-measurement draw bug reported in #5258. The renderer defect itself is already fixed on main by the trace rework in #4945 (included in v0.15.2_base); this adds an ascii-draw test so a gate that follows a measurement in the middle of a trace keeps its correct layer position.

The test builds a three-qubit trace with h, then mz on q2, then x on q2, and asserts the exact ascii output:

     ╭───╮╭───╮
q2 : ┤ h ├┤ x ├
     ╰───╯╰───╯

On 0.15.1 behavior this crashes instead of misrendering: layers_from_trace stored absolute instruction indices while boxes_from_trace pushed only gates, so a skipped measurement desynced the two and indexed out of bounds. Mirrors the existing LatexDrawTester.skipsNonGateInstructions case.

DCO: all commits signed off as required.

Test output (ctest -R DrawTester -LE gpu_required and friends, devcontainer cu12.6-gcc12, Release, no GPU in this environment):

 3/15 Test #299: qpp_DrawTester.skipsNonGateInstructions .........   Passed    0.02 sec
 5/15 Test #301: qpp_LatexDrawTester.skipsNonGateInstructions ....   Passed    0.02 sec
 8/15 Test #498: dm_DrawTester.skipsNonGateInstructions ..........   Passed    0.02 sec
10/15 Test #500: dm_LatexDrawTester.skipsNonGateInstructions .....   Passed    0.02 sec
13/15 Test #624: stim_DrawTester.skipsNonGateInstructions ........   Passed    0.02 sec
15/15 Test #626: stim_LatexDrawTester.skipsNonGateInstructions ...   Passed    0.02 sec
100% tests passed, 0 tests failed out of 15

pre-commit run --all-files --hook-stage pre-push passes on every hook except markdown-link-check, whose single failure is a pre-existing stale badge URL in the top-level README.md (untouched by this branch); all other checked files report OK.

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