feat(gates): support Toffoli/CCZ as elementary multi-qubit gates

[arnavk23]

• Add Toffoli/CCZ identifiers ("Tof", "Too", "Toffoli", "CCX", "CCZ") to MULTI_CONTROLLED_GATES in gates.jl
• Allow multi-qubit elementary gate strings (>=3 qubits) in _catch_input_gate_errors in data.jl when the gate type is a recognized multi-controlled gate
• Handle multi-qubit elementary names in unitary(...) by delegating to QCO.multi_controlled_gate:
  map Toffoli/CCX/Tof/Too -> controlled X (multi-controlled X)
  map CCZ -> controlled Z (multi-controlled Z)
• Add tests in gates_tests.jl validating Tof_1_2_3 and Toffoli_1_2_3 produce the Toffoli matrix

Closes #70

[arnavk23]

@harshangrjn please review this pr.

[harshangrjn]

@harshangrjn please review this pr.

Thank you @arnavk23! There are a few PRs pending, but I’ll get to this one soon.

[codecov]

Codecov Report

❌ Patch coverage is 70.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.91%. Comparing base (1b66c56) to head (c3fd2df).

Files with missing lines	Patch %	Lines
src/data.jl	70.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #78      +/-   ##
==========================================
- Coverage   96.06%   95.91%   -0.16%     
==========================================
  Files          13       13              
  Lines        1752     1761       +9     
==========================================
+ Hits         1683     1689       +6     
- Misses         69       72       +3     

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[arnavk23]

@harshangrjn please review this pr.

Thank you @arnavk23! There are a few PRs pending, but I’ll get to this one soon.

A reminder for the same.