Clear unavailable gravity measurements before each attempt

experiments/GRAVITY_PREPARED_ROUNDOFF_2026-09-17.md

@@ -33,9 +33,30 @@ Two separate requirements remain:
 
 Diagnostics retain the raw affine discrepancy, raw target defect, arithmetic
 estimate, and resulting target threshold separately. Nonfinite or negative
-norm inputs fail the assessment. A failed preparation leaves these measurements
-unavailable rather than reusing the preceding trial's values. Diagnostics also
-report whether compact gravity operator and inverse applications were selected.
+norm inputs fail the assessment. Each gravity attempt clears its correction
+norm and prepared-assessment measurements before the raw candidate preparation.
+An early preparation or inner-solve failure therefore leaves unmeasured values
+as NaN, rather than reusing the preceding attempt's values. Initial gravity
+completion follows the same rule. A failure in the corrected preparation can
+still retain that attempt's measured correction norm.
+
+The last completed inner solve's true defect and cumulative solve/iteration/
+failure/time counters have a different lifetime: a candidate that fails before
+calling the inner solver does not erase them. A line-search candidate rejected
+before invoking the gravity strategy does not begin an auxiliary attempt and
+leaves all last-attempt diagnostics intact. Diagnostic consumers must distinguish
+these meanings. Diagnostics also report whether compact gravity operator and
+inverse applications were selected.
+
+`lastLinearReportSpace` labels the retained `lastLinearSolve` report from the
+outer strategy's `Solve`. A later positivity-direction relift can fail while
+that outer report remains converged in reduced coordinates. The evaluation then
+reports `linear_solve_failure`; the auxiliary failure is reflected by the gravity
+failure counter and last completed inner true defect. Changing only the report
+space would incorrectly relabel the retained reduced-system norms. The full
+lifted Newton gate precedes feasibility repair; a repaired direction must pass
+its relift, descent check, and nonlinear acceptance, but is not claimed to solve
+the original Newton equations.
 
 Three focused tests, appended to `tests/solver/gravity_reduction.cpp`, cover
 large cancelling contributions, rejection of defects beyond either gate,
@@ -43,3 +64,17 @@ nonfinite measurements, and scaling over twenty-four orders of magnitude.
 The real stellar rejection must still be reproduced and reassessed; passing a
 synthetic arithmetic test alone establishes neither the hypothesis nor stellar
 convergence.
+
+
+## Reporting regression
+
+Branch `research/gravity-trial-diagnostics-20260917` moves this reset to a shared
+attempt-entry helper, used by both trial strategies and initial completion.
+Existing production rollback fixtures now assert finite measurements after a
+completed curvature assessment, and unavailable prepared/correction fields after
+a failed initial inner solve while retaining its finite true defect and counters.
+No new stellar fixture or numerical behavior is introduced. The source-level
+success-then-early-failure path is covered by the unconditional shared reset;
+a separate expensive campaign is not justified for this reporting change.
+Build/run of the added assertions is deferred until the running immutable
+production campaign completes.