tulpa 0.0.134

• fit_st_nested()'s auto-recenter no longer switches itself off when a grid
  knob is set to the engine's own default value (#294). The
  spatiotemporal rescue guarded on the PRESENCE of any of tau_lower,
  tau_upper, n_grid_spatial, n_grid_temporal, n_grid_rho, rho_lower,
  rho_upper in control, so control = list(n_grid_spatial = 4L) -- 4L being
  the default -- returned at the first guard and left a railed grid railed. That
  is #293 one level down: a wrapper package exposing its own
  n_grid argument, defaulted to the engine's value, threads it through on
  every fit and disabled the rescue for all of them. A knob is now a PIN only
  when its value differs from .nl_st_default() and it carries no
  [auto_grid()] mark, the same provenance question the three grid-vector
  rescues ask.

  Pinning is also PER AXIS rather than all-or-nothing: tau_lower / tau_upper
  hold the two precision axes (they build both), n_grid_spatial /
  n_grid_temporal one each, and n_grid_rho / rho_lower / rho_upper the
  ar1 autocorrelation axis. A pinned axis keeps exactly the nodes its knobs
  built and is named in the new outer_grid_pinned_axes; the rest are recentred
  as usual. Only when EVERY axis is pinned does the rescue decline outright.

• auto_grid() now marks a scalar knob or a prior specification, not just a
  grid vector. One front door for "this value is my default, not the user's
  choice", across the three shapes that question arises in.

• The auto-recenter's second-attempt PC prior is no longer suppressed by a
  prior_sigma the caller merely supplied (#297). The escalation
  that exists for a runaway, near-separation mode engaged only when
  prior_sigma was NULL, so a wrapper stamping a prior_sigma of its own
  turned attempt 2 into a second geometry recenter while the fit still reported
  outer_grid_recenter_attempts = 2 as if the full escalation had run. The
  suppression is now decided by provenance -- an auto_grid()-marked spec, or
  one equal by value to the engine's own PC(U = 3, alpha = 0.01), is a default
  and does not hold the prior back -- and when a genuine pin does suppress it
  the fit carries outer_grid_prior_declined = "prior_pinned".

• The outer Pareto-k now says WHY it declined (#295). Roughly
  two dozen distinct decline paths all arrived as the single value
  pareto_k = NA, and the print method admitted as much ("outer diagnostic not
  run or proposal degenerate"). "You turned it off", "this family's support can
  never be scored", "the outer Hessian came back non-finite" and "the weights
  carry no mass" are not interchangeable, and a batch reading pareto_k across
  many fits could not tell a permanent structural limitation from a live signal
  about the fit. Every decline now carries a reason from a closed vocabulary in
  fit$pareto_k_declined: "not_requested", "not_applicable",
  "unguessable_axis" (naming the axis, e.g. car_proper's rho_car -- read the
  quadrature ESS instead, permanently), "draws_too_few", "grid_too_small",
  "no_varying_axis", "degenerate_proposal", and
  "internal_inconsistency" (an engine bug, which diagnostic_summary() now
  WARNs on). Wired through the joint single- and multi-block paths, the
  registry path, the SPDE grid and CCD paths, and the shared IS cores;
  surfaced by diagnostics(), print.laplace_diagnostics() and
  diagnostic_summary().

• The inner-Laplace gamma_3 diagnostic now says why it declined too
  (#296). gamma_3 never returns a silently-wrong 0
  (#272), but its NaN carried no reason, so a structurally
  unscorable model -- a coupled multi-process likelihood such as tulpaObs's
  occu_cover, which this formula can never score -- printed as
  control$diagnose_skew = FALSE, attributing an impossibility to a knob the
  user had most likely left at its default TRUE. The reason now travels from
  the point of decline: build_spec_curvature3_fn() reports
  "coupled_likelihood" / "curvature3_unavailable" through an out-parameter
  rather than a second predicate that could drift from it, the per-arm oracles
  travel as a JointCurvature3Oracles carrying "coupled_arm" and which arms
  it applies to, and the R side adds "not_requested", "no_probe_indices",
  "backend_unsupported" and "solve_failed". Reported on the fit as
  inner_skew_declined / inner_skew_arms_declined -- the latter also on a
  PARTIALLY scored joint fit -- and read back by the combined verdict, which
  now distinguishes a layer that was not assessed from one that is unscorable
  by construction (for those models the outer k-hat is the only reliability
  number available, permanently).

• Fixed: .nl_inner_skew_at_theta() guarded its probe with return(NULL)
  written inside a tryCatch() expression (#298). That returns from
  the ENCLOSING function, so a fit hitting any of those guards had the whole
  res replaced by NULL by a diagnostic that was only meant to decline. The
  probe is now its own function.