from research import *
s=begin(871,'Checkpoint the complete new display transfer','What has the cycle established after40 actions?',{'completed_before_checkpoint':39},['C832–870'])
prefix=[r for r in json.loads((ROOT/'journal.json').read_text()) if r['step']<=870]
body="""# Chronological families: checkpoint after C871

Forty sequential actions now extend the C831 framework across complete source objects.

The list families require category membership and declared order; their margins alone lose information. The complete festival walks and household partitions make that loss explicit.

File_52c contributes32 paired sources and64 original-span reversals. Decimal borrowing, changes of core length and retained zeros explain every paired difference. No second inversion or new statistical tally is used.

The complete78-row NT display follows one civil70-year index. Its22-node shared Genesis field is recovered from local edge differences and terminal1710. Restoring Cainan aligns23 names but retains different edge measures. The entire primary display shares a490-year coarsening with the derived49-grid. Its reflection is automatic grid closure; the BJ markings remain supplied placements.

The next question is how these complete objects constrain admissible Key domains and retained internal subdivisions. Source arithmetic is being explained; historical origin and intentional composition are not established.

The source controls from C831 remain active, including latest File_52c, local source snapshots, restricted Gear scope, quarantined primers, phase and civil/Rounded distinctions.
"""
a=artifact('deliverables/490d_Chronological_Families_Checkpoint_C871.md',body)
finish(s,{'checkpoint':a,'prefix_actions':len(prefix)},'The complete NT family transfers to the same ordered-path and measurement grammar. Its new contribution is whole-field reconstruction, finite lattice classification and common coarsening, not additional isolated dates.','Freeze the complete operator packet and derive the general grid-preservation condition.',{'prefix':len(prefix)==39,'last':prefix[-1]['step']==870})