🔖 Prepare release of v3.3.0 (#738)

## Description

This PR prepares the release of v3.3.0.

## Checklist:

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

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Changed**
  * Raised the minimum supported core component version.
* Ended support for Python 3.9; testing and wheel distributions updated
accordingly.

* **Documentation**
  * Added release notes for version 3.3.0 with upgrading guidance.
  * Documented Python 3.9 end-of-life and its implications.
* Updated changelog with new version references, comparison links, and
PR reference.
* Refreshed “Unreleased” links to point from the previous release to
v3.3.0.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Daniel Haag <121057143+denialhaag@users.noreply.github.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: denialhaag

CHANGELOG.md

@@ -9,10 +9,18 @@ This project adheres to [Semantic Versioning], with the exception that minor rel
 
 ## [Unreleased]
 
+## [3.3.0] - 2025-10-14
+
+_If you are upgrading: please see [`UPGRADING.md`](UPGRADING.md#330)._
+
 ### Added
 
 - 👷 Enable testing on Python 3.14 ([#730]) ([**@denialhaag**])
 
+### Changed
+
+- ⬆️ Bump minimum required `mqt-core` version to `3.3.1` ([#735]) ([**@denialhaag**])
+
 ### Removed
 
 - 🔥 Drop support for Python 3.9 ([#704]) ([**@denialhaag**])
@@ -84,14 +92,16 @@ _📚 Refer to the [GitHub Release Notes] for previous changelogs._
 
 <!-- Version links -->
 
-[unreleased]: https://github.com/munich-quantum-toolkit/qcec/compare/v3.2.0...HEAD
+[unreleased]: https://github.com/munich-quantum-toolkit/qcec/compare/v3.3.0...HEAD
+[3.3.0]: https://github.com/munich-quantum-toolkit/qcec/releases/tag/v3.3.0
 [3.2.0]: https://github.com/munich-quantum-toolkit/qcec/releases/tag/v3.2.0
 [3.1.0]: https://github.com/munich-quantum-toolkit/qcec/releases/tag/v3.1.0
 [3.0.0]: https://github.com/munich-quantum-toolkit/qcec/releases/tag/v3.0.0
 [2.8.2]: https://github.com/munich-quantum-toolkit/qcec/releases/tag/v2.8.2
 
 <!-- PR links -->
 
+[#735]: https://github.com/munich-quantum-toolkit/qcec/pull/735
 [#730]: https://github.com/munich-quantum-toolkit/qcec/pull/730
 [#704]: https://github.com/munich-quantum-toolkit/qcec/pull/704
 [#699]: https://github.com/munich-quantum-toolkit/qcec/pull/699

UPGRADING.md

@@ -4,6 +4,8 @@ This document describes breaking changes and how to upgrade. For a complete list
 
 ## [Unreleased]
 
+## [3.3.0]
+
 ### End of support for Python 3.9
 
 Starting with this release, MQT QCEC no longer supports Python 3.9.
@@ -62,7 +64,8 @@ Alternatively, CMake can be conveniently installed from PyPI using the [`cmake`]
 
 <!-- Version links -->
 
-[unreleased]: https://github.com/munich-quantum-toolkit/qcec/compare/v3.2.0...HEAD
+[unreleased]: https://github.com/munich-quantum-toolkit/qcec/compare/v3.3.0...HEAD
+[3.3.0]: https://github.com/munich-quantum-toolkit/qcec/compare/v3.2.0...v3.3.0
 [3.2.0]: https://github.com/munich-quantum-toolkit/qcec/compare/v3.1.0...v3.2.0
 [3.1.0]: https://github.com/munich-quantum-toolkit/qcec/compare/v3.0.0...v3.1.0
 [3.0.0]: https://github.com/munich-quantum-toolkit/qcec/compare/v2.8.2...v3.0.0