💥 Align compiler terminology and public names

[burgholzer]

🤖 AI text below 🤖

Description

Align the compiler-facing C++, Python, CLI, diagnostics, and documentation with the glossary and the naming decisions in #2251 and PR #2149. OpenQASM import now uses version-generic names for its supported versionless, 2.0, 3.0, and 3.1 inputs. Target metadata is CompilerTarget.OperationCapability / CompilerTarget::OperationCapability, and mqt-cc advertises and defaults to --emit=qc.

These are clean renames of unreleased v4 interfaces: old import spellings and CLI aliases are removed. The audit and migration table records all replacements, downstream checks, and retained terminology. All in-tree callers, binding patterns, generated stubs, tests, and examples are updated.

Correct jeff conversion versus serialization, barrier operations, canonicalization patterns, conversion targets, linear ownership, and static entry-point gate counts. Compilation behavior and the accepted language subset are preserved. The requested Ponytail review removed one forwarding helper and found no remaining complexity to cut. No dependencies are added.

Local validation:

• Native Clang 23/LLVM-MLIR 23.1 release build with ThinLTO; 3,505 native tests passed, one existing sample-device job-ID test skipped.
• 653 Python compiler, Qiskit, and QCO DD tests passed on each of Python 3.11–3.14; the final versionless-input example also passed all four focused version cases.
• Stub generation, executable documentation and generated-link checks, repository lint, and full-file C++ lint passed.
• Hosted CI is separate from these local results.

The existing v4 changelog entry and upgrade-guide examples use the final terminology.

Codex assisted with the audit, implementation, tests, review, and this description. Human review remains required before merge.

Fixes #2251

Checklist

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• I have added migration instructions to the upgrade guide (if needed).
• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

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[codecov]

Codecov Report

❌ Patch coverage is 96.70330% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...lib/Dialect/QC/Translation/OpenQASMToQCEmitter.cpp	90.4%	2 Missing ⚠️
mlir/lib/Compiler/Programs.cpp	80.0%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[burgholzer]

This feels like a pretty solid coverage and streamlining of the terminology for now. I'll get this in now to avoid large conflicts 🚀