Preserve Tier2 crossover carrier map subsets

docs/rehost-queue/README.md

@@ -6,7 +6,7 @@ useful as evidence, but should not stay in the short active queue file.
 - `archive-2026-04-19.md`: preserved detailed queue snapshot from the pre-index cleanup.
 - `periodic-company-control-lane-2026-04-21.md`: checked compact-dispatch/control-lane evidence
   for the active periodic-company queue head.
-- `tier2-candidate-row-families-2026-04-21.md`: checked candidate-table row-family split for the
-  active Tier-2 `0x00412d70` queue head.
+- `tier2-candidate-row-families-2026-04-21.md`: checked candidate-table row-family, trailer-family,
+  and crossover carrier-map split for the active Tier-2 `0x00412d70` queue head.
 - `tier2-selector-byte-sources-2026-04-21.md`: checked stock `BuildingTypes` selector-byte and
   alias-root evidence for the active Tier-2 `0x00412d70` queue head.

docs/rehost-queue/tier2-candidate-row-families-2026-04-21.md

@@ -50,6 +50,29 @@ The new crossover field keeps the row-family and trailer-family interaction expl
 
 So the row shift and numbered trailer split do not collapse to one underlying map family.
 
+## Mixed Carrier Sets
+
+The checked crossover paths keep the mixed subfamilies concrete too:
+
+- off-row `10/18 :: 0x00000001`
+  - `Crossing the Alps.gmp`
+  - `Go West!.gmp`
+  - `Rhodes Unfinished.gmp`
+- off-row `10/18 :: 0x00000000`
+  - `East Coast, USA.gmp`
+  - `Germany.gmp`
+  - `State of Germany.gmp`
+  - `War Effort.gmp`
+- ordinary-row `35/43 :: 0x00000000`
+  - `Britain.gmp`
+  - `British Isles.gmp`
+  - `Greenland Growing.gmp`
+  - `Ireland.gmp`
+  - `Spanish Mainline.gmp`
+
+So the `0x00000000` trailer lane is not merely “the off-row `10/18` family.” It also survives on
+one smaller ordinary-row `35/43` subset.
+
 ## Immediate Reading
 
 This keeps the Tier-2 frontier narrower than a generic “candidate table varies by scenario” claim: