docs: record the routing cause and the three silent-failure guards

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011oLWY1G6S8U35bi2FxVWni

README.md

@@ -166,14 +166,33 @@ those types set `IncludeInPhysical = false` — they are blueprint stat-display
 plumbing and carry no signal on a real ship, so every receiver read off, the
 vent gate was permanently open, and radiators behaved exactly as in vanilla.
 
-**v1.1.0** carries the signals as `NetworkValue` / `NetworkValueReceiver`
+**v1.1.0** carried the signals as `NetworkValue` / `NetworkValueReceiver`
 instead, which is what vanilla's thermal amplification pump uses to drive actual
-physical behaviour, and which never sets `IncludeInPhysical` anywhere in the
-shipped data. `tests/test_mod.py` now fails on any use of the blueprint-only
-types, and separately re-checks that premise against the installed game so the
-guard cannot quietly go stale.
+physical behaviour. That was necessary but not sufficient: it also loaded
+cleanly and did nothing.
 
-The v1.1.0 logic is verified statically but has not yet been confirmed in-game.
+**v1.2.0** added the diagnostic indicator icons, which is what finally located
+the fault. The wrench icon was present — so `AddBase` and the `Overrides` had
+been applying correctly the whole time — while both signal icons showed,
+meaning both `NetworkValue`s read zero.
+
+**v1.3.0** fixes the actual cause. A network component is only attached to the
+network if a **route** reaches it: the part's `NetworkPort` anchors on one
+component, and a `NetworkRouter` bridges that anchor to every other network
+component on the part. That is how vanilla connects the radiator's own
+`NetworkedThermalDissipationLoadValue`, and how the amplification pump reaches
+the resonance beam turret. Unrouted components are not an error — they simply
+never connect and read as absent forever.
+
+Routes were added from each part's anchor: `NetworkedHeatBuffer` on the radiator
+through its existing `Router`, plus a new `NetworkRouter` on the thermal
+battery, the missile launcher and `base_part_overclock`, none of which ships
+one.
+
+Three separate mechanisms have now each produced a mod that loads without a
+single error and silently does nothing. The test suite has a mutation-verified
+guard for each: blueprint-only signal types, fields that do not exist in the
+real schema, and unrouted network components.
 
 ## Possible additions