FEAT: add generate_qn_transitions function

[grayson-helmholz]

• Closes Illustrate 4- or even 5-body isobar decay in the visualization notebook #27
• Closes Generalize output transitions and IO beyond State/ParticleWithSpin #341

✨ New features

• generate_qn_transitions() is the quantum-number-level counterpart of generate_transitions(). It chains create_qn_problem_sets(spin_projections=False) with find_qn_transitions() and returns a QNReactionInfo. Because the spin-projection combinatorics is avoided both in the problem sets and in the constraint problem, it stays feasible for many-body final states, where generate_transitions() takes impractically long.
• QNReactionInfo collects the resulting QNTransitions. Its initial and final states are Particle instances, while each intermediate state stays a property map of the quantum numbers that any particle appearing there must carry. It offers get_intermediate_quantum_numbers() to list those distinct sets and group_by_topology(), mirroring ReactionInfo.
• find_qn_transitions() and collect_qn_transitions() take an optional particle_db with which they resolve the external states, which are fully determined by their pid, to Particle instances. Intermediate states are deliberately left as property maps, since they stand for a set of allowed states rather than one particle.
• create_qn_problem_sets() accepts allowed_interaction_types (for instance "strong" or ["em", "weak"]), which restricts the interaction types of the default or given interaction_config without the caller having to build an InteractionConfig by hand. The given config is copied rather than mutated.

⚙️ Enhancements

• collapse_graphs() (the collapse="topology" rendering option) now handles states that are quantum-number property maps. Such a state is reduced to the new QuantumNumberSignature, which renders as the PDG-style $I^G(J^{PC})$ summary, so a collapsed edge lists signatures such as 1⁺(1⁻⁻) instead of full property maps. The signature has both a plain and a LaTeX rendering, and the label formatters gained a superscript() method for it.
• The DOT and Mermaid printers accept a QNReactionInfo wherever they accept a ReactionInfo, so quantum-number transitions can be visualized with the usual qrules.io entry points.
• to_state_definitions() moved from a private helper in qrules to the public API of qrules.combinatorics, since the quantum-number workflow needs the same normalization of a single state definition into a list.

Squash commit messages

* DOC: illustrate four- and five-body decays
* ENH: collapse quantum-number transitions by topology
* ENH: render QNReactionInfo as DOT and Mermaid
* FEAT: add allowed_interaction_types argument
* FEAT: add QNReactionInfo class
* FEAT: make to_state_definitions public