Normalize CallbackAffectPWrapper VJP argument ordering

[ChrisRackauckas-Claude]

Summary

• Normalizes CallbackAffectPWrapper signature from (dp, p, u, t) to (dp, u, p, t) to match the standard (du, u, p, t) convention
• Uses the dgrad output path (p-derivative) in vecjacobian! instead of hijacking the dλ path (u-derivative) via swapped arguments
• Adds _get_wp_paramjac_config helper for correct param-sized output buffers in Enzyme and ReverseDiff VJP paths

This unblocks PRs #1335, #1292, #1260, #1223 that need SciMLStructures support, where canonicalize(Tunable(), _p) was running on state y instead of actual parameters (because integrator.p was passed in the y position), and Enzyme code assumed position 2 is a state-like object.

Files changed

• src/callback_tracking.jl — Signature change, normalized vecjacobian! calls, added _get_wp_paramjac_config helper, replaced get_paramjac_config with param-aware version
• src/derivative_wrappers.jl — ReverseDiff on-the-fly tape: CallbackSensitivityFunctionPSwap dispatch for param-sized output buffer
• src/quadrature_adjoint.jl — QuadratureAdjoint callback path: normalized wp call order, vecjacobian! args, and paramjac config

Test plan

• Callbacks1 test group passes all 360 tests locally (Julia 1.12.4)
• Verified unmodified code also passes 360 tests (baseline comparison)
• Critical test cases exercised: "parameter changing callback", "Dosing example", all sensealg variants (BacksolveAdjoint, InterpolatingAdjoint, QuadratureAdjoint, GaussAdjoint, ReverseDiffAdjoint)

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