feature: Add a QIR to OpenQASM translator

[keyiyin233]

Description of changes:

• Add the initial QIR → OpenQASM 3 translator implementation.
• New/updated modules:
  • builder.py – Builder hierarchy (FunctionBuilder, InstructionBuilder, DeclBuilder, etc.) plus SymbolTable for type/variable tracking and QIR→QASM lowering.
  • cfg_pattern.py / control_flow.py – Control-flow graph utilities and pattern-matching helpers for translating LLVM br into structured if/while OpenQASM constructs.
  • qir_profile.py – Profile and BaseProfile definitions that register the standard builder for QIR structures (Qubit, Result), classical instructions, and standard QIS functions in QIR.
  • translator.py – High-level Exporter and QASM3Builder that parse an LLVM ModuleRef, build the OpenQASM 3 AST, and emit a complete program with includes, variable declarations, gate definitions, and translated main body.
• Supports:
  • Direct QIS gate mapping (e.g., __quantum__qis__h__body → h).
  • Classical arithmetic ops (add, sub, mul) via BinaryExpressionBuilder.
  • Measurement, reset, defcal placeholders for opaque QIR functions.
  • Symbol-table–driven type conversion (type_qir2qasm) and temporary/IO variable allocation.
  • Support the translation of CFG with Simple single-exit loop (one back-edge, one exit) and Nested single-exit loops.

Testing done:

• Unit tests for individual builders (gate, measurement, arithmetic) verifying correct OpenQASM 3 AST output.
• End-to-end test: translated a sample CUDA-Q generated QIR module containing allocations, measurements, and classical branches.
• Verified correct generation of OpenQASM 3 while/ if blocks with expected conditions and body statements.

Merge Checklist

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General

• I have read the CONTRIBUTING doc
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Tests

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (a94c25b) to head (2e2ae01).

Additional details and impacted files

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  Files           48        54     +6     
  Lines         1997      2841   +844     
  Branches       228       337   +109     
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+ Hits          1997      2841   +844     

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