feat: require Python 3.12

[Jammy2211]

Summary

Raise PyAutoFit's minimum supported Python version to 3.12 and advertise only Python 3.12 and 3.13.

Remove the now-tautological Optax interpreter marker while preserving its existing lower bound, and replace two Python-3.7-era ABC aliases with direct typing.Protocol definitions.

Refs #1428.

API Changes

Public PyAutoFit symbols and signatures are unchanged. Installation now requires Python 3.12 or newer; internal graphical interface annotations are real typing.Protocol classes rather than ABC aliases.
See full details below.

Test Plan

• Graphical subsystem on Python 3.12: 219 passed
• Full Python 3.12 suite: 1559 passed, 1 skipped
• Full Python 3.13 suite: 1559 passed, 1 skipped
• Wheel metadata: Requires-Python >=3.12; classifiers 3.12/3.13 only; optax>=0.2.5 preserved without a Python marker
• Curated ecosystem smoke: 57 passed, 5 parallel failures, 3 intentional skips; sequential retry passed 4/5, with only the exact previously accepted 300-second imaging/subhalo_recovery.py timeout remaining
• Independent Claude Opus 5 review: CLEAN
• Heart: YELLOW score 65, exact previously acknowledged campaign reason set, no RED

Validation checklist (--auto run — plan was not pre-approved)

• Effective level: safe (header: supervised, cap: feature medium → safe)
• Plan: on issue feat: require Python 3.12 #1428, written at start, unmodified since
• Gate: tests 3.12 1559 passed/1 skipped + 3.13 1559 passed/1 skipped · smoke accepted identical non-causal timeout after 4/5 sequential retries passed · review CLEAN · Heart YELLOW within launch acknowledgement
• Human: plan sound in hindsight?
• Human: diff matches plan (no scope creep)?
• Human: campaign merges authorized contingent on exact reviewed head and green CI

Full API Changes (for automation & release notes)

Changed Behaviour

• Package installation now requires Python 3.12 or newer.
• autofit.graphical.factor_graphs abstract and jacobian interface classes are genuine typing.Protocol objects. They are annotation-only, not publicly re-exported, and have no runtime consumer in PyAutoFit or downstream repositories.
• The jax extra installs optax>=0.2.5 without an interpreter marker; this is equivalent on every supported interpreter.

Migration

• Recreate environments on Python 3.12 or newer before installing the next PyAutoFit release.
• External code importing the internal FactorInterface classes should use them as static protocols, not instantiate them or apply isinstance checks.

Generated by the PyAutoLabs agent workflow.