Assign field semantics to plugin owner

docs/eve-migration-roadmap.md

@@ -107,6 +107,10 @@ advertisements and typed command/receipt documents are the boundary.
   RUDP operation envelopes. A Sai surface may request
   nested Norn or TeX capabilities when those plugins are available.
 - EvePlugins owns the TeX sidecar and KaTeX-backed semantic witness.
+- EvePlugins owns the independent `fields.surface` sidecar, generic
+  `gamecult.fields.*` document model, fixtures, tests, and CultNet witness.
+  Aetheria remains owner of sampled field truth; runtimes remain owners of
+  native field projection.
 - The TeX owner sidecar serves its Eve ABI over CultNet RUDP operation
   envelopes; its stdio protocol is retained only as a local debug adapter.
 - Aetheria owns its provider advertisement, world surface, scenario, asset
@@ -151,6 +155,10 @@ advertisements and typed command/receipt documents are the boundary.
   is its semantic owner. Sai already owns VN/Ink execution and its live witness.
 - Keep nested plugin availability explicit and non-transitive: Sai does not own
   Norn or TeX.
+- Migrate Aetheria viewport publications from `gamecult.aetheria.*_viewport`
+  arrays to the `fields.surface` document model, then delete the Aetheria schema
+  decoders from Hermodr and move browser field projection behind a runtime
+  adapter for the advertised plugin.
 
 ### Conformance
 

docs/plugin-architecture.md

@@ -467,6 +467,16 @@ Sai surface deploys with nested Norn or TeX, Sai composes the slots and keeps VN
 stage authority; Norn and TeX still publish and validate their own semantic
 contracts. Each plugin advertises only the ABI operations it actually owns.
 
+### Semantic Fields
+
+`fields.surface` owns `field.surface2d` and `gravity.surface` semantics plus the
+generic `gamecult.fields.*` document family. Providers own sampled scalar,
+vector, color, mask, and object documents. The plugin validates and projects
+those documents through the executable ABI; browser, Unity, and other runtimes
+own native canvas, shader, texture, or scene projection. A provider-specific
+field schema or array layout is not Eve core and must not be decoded inside a
+generic runtime transport.
+
 The carrier does not define the plugin. UTF-8 NDJSON over stdio remains a local
 debug adapter: one request document per line, one response per request in
 order, blank lines ignored, diagnostics on stderr. The production sidecar path