Revert the revert of G's mesh-sdk merge (#191): G's sdk stands again over reader release 3

Main reverted G's half merge (#189, reverted by 8afc3eb in #191) and then took the reader release's S1-S5, which
copied G's code. G's form holds where they differ (process_bus.go, seats.go, state.go and their tests); the
release's kept names stay so main's callers keep building: SeatViewPrefix beside SeatReadPrefix, and QueueInvoke's
empty strings on not-ok (with its test TestQueueInvoke). The tree differs from G's head f30dee54 only by those and
the release's two tests (objects cap option, seat states and stream kinds).

Builds: design 47 G (the milestone's sdk part, as at f30dee54)

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@novox/mesh-sdk",
-  "version": "0.1.18",
+  "version": "0.1.19",
   "description": "The stable spine a Novox Mesh module's own code builds against.",
   "type": "module",
   "exports": {
@@ -12,7 +12,10 @@
     "./events": "./dist/events/index.js",
     "./primitives": "./dist/primitives/index.js",
     "./stdio": "./dist/stdio/index.js",
-    "./state": "./dist/state/index.js"
+    "./state": "./dist/state/index.js",
+    "./callers": "./dist/callers/index.js",
+    "./runtime": "./dist/runtime/index.js",
+    "./views": "./dist/views/index.js"
   },
   "files": [
     "dist"