feat(simulation): lakes from settled hydrology (D-227, T-1184)

Productionizes the T-1177 equilibrium solver: run_layer1 now solves
hydrology once per body (~24ms, mirrors drainage::analyze) and carries
it as TerrainAnalysis.hydrology; run_layer1_with_moisture threads the
real body moisture ceiling (extracted derive_moisture_ceiling_q), with
the T-1177 population-survey default as fallback. The resident rung-0
global tier does not exist yet (T-1181's scope) — hydrology rides
TerrainAnalysis and lands in that tier for free when it is built
(deviation recorded on the ticket).

MorphologyZone::Lake is now sourced from the settled solver at derive
time: a gridunit is Lake when bilinear-sampled filled surface exceeds
bilinear-sampled original elevation at the sample's own (px, py) — the
continuous comparison, so lake edges refine with rung like coastlines;
never a discrete basin-cell projection. The gate sits strictly between
OpenOcean (>= 80) and the old ocean_fraction heuristic (>= 60), which
survives as the derive-fresh fallback when no solve is attached —
byte-identical to pre-T-1184 output in that case. Static
classification, distinct from the sim-state flooded plane; no
endorheic bit (the drains-vs-closed cue is T-1185's outlet-course
presence, per the D-227 amendment (4) sequencing). Zero new wire
bytes.

Acceptance: lake_classification_cache_hit_equals_cache_miss (solve
twice independently, byte-identical zones, non-vacuous Lake hit) plus
hydrology determinism tests. Golden fidelity: the window golden
fixture now builds TerrainAnalysis through the production entry point
(run_layer1_with_moisture, per-body), and a dedicated lake_bowl golden
body pins the hydrology-sourced Lake path (morphology 1 at
ocean_fraction_q 0 — provably not the heuristic); the 108 pre-existing
golden rows are byte-identical (pure append). believability.json moved
by one lake-shaped line (GJ338Bd voxel_relief_m 27->28, a correctly
reclassified lake district leaving the dry-relief sample set).
river_course and derivation-harness goldens unchanged. Full suite:
2114 passed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/tests/golden/believability.json

@@ -28,7 +28,7 @@
       "morphology_zones": 9,
       "vegetation_classes": 4,
       "terrain_materials": 4,
-      "voxel_relief_m": 27,
+      "voxel_relief_m": 28,
       "micro_habitat_distinct": 2
     },
     "coherence": {

server/tests/golden/window_derivation_golden.json

@@ -916,5 +916,107 @@
     "temperature_dc": 480,
     "moisture_q": 47,
     "vegetation": 3
+  },
+  {
+    "label": "lake_bowl/lake_centre",
+    "rung": "district",
+    "wx_m": 20015086,
+    "wy_m": 158849,
+    "min_wl_m": 4096,
+    "morphology": 1,
+    "tectonic": 0,
+    "glaciation": 0,
+    "precipitation": 3,
+    "slope_q": 4,
+    "elev_q": 0,
+    "ocean_fraction_q": 0,
+    "temperature_dc": 62,
+    "moisture_q": 56,
+    "vegetation": 6
+  },
+  {
+    "label": "lake_bowl/lake_centre",
+    "rung": "quarter",
+    "wx_m": 20015086,
+    "wy_m": 158849,
+    "min_wl_m": 1024,
+    "morphology": 1,
+    "tectonic": 0,
+    "glaciation": 0,
+    "precipitation": 3,
+    "slope_q": 5,
+    "elev_q": 0,
+    "ocean_fraction_q": 0,
+    "temperature_dc": 62,
+    "moisture_q": 56,
+    "vegetation": 6
+  },
+  {
+    "label": "lake_bowl/lake_centre",
+    "rung": "region",
+    "wx_m": 20015086,
+    "wy_m": 158849,
+    "min_wl_m": 0,
+    "morphology": 1,
+    "tectonic": 0,
+    "glaciation": 0,
+    "precipitation": 3,
+    "slope_q": 0,
+    "elev_q": 0,
+    "ocean_fraction_q": 0,
+    "temperature_dc": 62,
+    "moisture_q": 56,
+    "vegetation": 6
+  },
+  {
+    "label": "lake_bowl/lake_rim",
+    "rung": "district",
+    "wx_m": 1250942,
+    "wy_m": 158849,
+    "min_wl_m": 4096,
+    "morphology": 8,
+    "tectonic": 0,
+    "glaciation": 2,
+    "precipitation": 1,
+    "slope_q": 0,
+    "elev_q": 71,
+    "ocean_fraction_q": 0,
+    "temperature_dc": -120,
+    "moisture_q": 55,
+    "vegetation": 1
+  },
+  {
+    "label": "lake_bowl/lake_rim",
+    "rung": "quarter",
+    "wx_m": 1250942,
+    "wy_m": 158849,
+    "min_wl_m": 1024,
+    "morphology": 8,
+    "tectonic": 0,
+    "glaciation": 2,
+    "precipitation": 1,
+    "slope_q": 2,
+    "elev_q": 75,
+    "ocean_fraction_q": 0,
+    "temperature_dc": -120,
+    "moisture_q": 54,
+    "vegetation": 1
+  },
+  {
+    "label": "lake_bowl/lake_rim",
+    "rung": "region",
+    "wx_m": 1250942,
+    "wy_m": 158849,
+    "min_wl_m": 0,
+    "morphology": 8,
+    "tectonic": 0,
+    "glaciation": 2,
+    "precipitation": 1,
+    "slope_q": 0,
+    "elev_q": 70,
+    "ocean_fraction_q": 0,
+    "temperature_dc": -120,
+    "moisture_q": 54,
+    "vegetation": 1
   }
 ]