Replaces terminate-at-first with chaining through the basin graph (rivers/04): one D8 field on
FullFilled per seed; each promoted river follows it from its terminal, checked at every basin
entered against the floor→spill climb (SpillClimbM) vs ISLA_FLOW_CAP_M (30) — overflow or wall.
Lake basins are entered on the real terrain (Plan.Dir, rivers/03c fix B fallback), crossed as
water to the entered body's lowest-FullFilled outlet, left over the spill. Keep on OceanMask /
IsLake, drop on dry or puddle-only, read through the rivers/03b confluence root (reused verbatim).
The field at the cap (walled basins re-pointed onto the real terrain), its accumulation and every
cell's destination; hero-lake candidates ranked as data. HydrologyRenderer: the showpiece map on
the atlas relief and the flow-direction data map. Heights digested and asserted; nothing filled,
nothing carved. RiverRouting.Confluence and DrainageRenderer.LabelPlacer private→internal.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EppUMXNhSeuA5Mu51UnTyP
beezm
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