feat(frontend,wire): surface system (FE slice 1) + @dispatch/wire types-only split (B2)

FE slice 1 — backend-declared, frontend-agnostic surface system (verified live): new types-only @dispatch/ui-contract (SurfaceSpec / field kinds / region / ActionRef / catalog), surface-registry (typed service handle), transport-ws (Bun WS :24205, path-agnostic upgrade), surface-loaded-extensions (first real surface); kernel HostAPI.getExtensions; host-bin wiring; bin/up. Harness: retire AGENTS 'backend only', ORCHESTRATOR §3/§7/§8, frontend-design.md locked.

B2 — wire-types split (chat-slice prerequisite): new types-only @dispatch/wire single-sources the wire ABI (AgentEvent + 11 variants; conversation model Chunk/ChatMessage/Role/TurnId/StepId + 6 chunk variants; Usage) with zero @dispatch/* deps. @dispatch/kernel re-exports via shims so its public surface is byte-identical (zero consumer blast radius). transport-contract re-exports AgentEvent from @dispatch/wire and drops its @dispatch/kernel dependency, so HTTP clients (the web frontend) consume the wire without the kernel runtime.

tsc -b + biome clean; 460 vitest + 77 bun pass.

3 files changed, 16 insertions, 7 deletions

diff --git a/packages/host-bin/package.json b/packages/host-bin/package.json
index 4ce63a9..65e986d 100644
--- a/packages/host-bin/package.json
+++ b/packages/host-bin/package.json
@@ -13,6 +13,9 @@
 		"@dispatch/session-orchestrator": "workspace:*",
 		"@dispatch/transport-http": "workspace:*",
 		"@dispatch/tool-read-file": "workspace:*",
-		"@dispatch/journal-sink": "workspace:*"
+		"@dispatch/journal-sink": "workspace:*",
+		"@dispatch/surface-loaded-extensions": "workspace:*",
+		"@dispatch/surface-registry": "workspace:*",
+		"@dispatch/transport-ws": "workspace:*"
 	}
 }
diff --git a/packages/host-bin/src/main.ts b/packages/host-bin/src/main.ts
index d766e46..68cbbdd 100644
--- a/packages/host-bin/src/main.ts
+++ b/packages/host-bin/src/main.ts
@@ -21,8 +21,11 @@ import {
 import { extension as providerOpenaiCompatExt } from "@dispatch/provider-openai-compat";
 import { extension as sessionOrchestratorExt } from "@dispatch/session-orchestrator";
 import { createSqliteStorage, extension as storageSqliteExt } from "@dispatch/storage-sqlite";
+import { createLoadedExtensionsExtension } from "@dispatch/surface-loaded-extensions";
+import { createSurfaceRegistryExtension } from "@dispatch/surface-registry";
 import { extension as toolReadFileExt } from "@dispatch/tool-read-file";
 import { createServer, extension as transportHttpExt } from "@dispatch/transport-http";
+import { createTransportWsExtension } from "@dispatch/transport-ws";
 import type { ChildHandle } from "./collector-supervisor.js";
 import { createCollectorSupervisor } from "./collector-supervisor.js";
 import { configMapToAccess, envToConfigMap } from "./config.js";
@@ -61,6 +64,10 @@ const CORE_EXTENSIONS: readonly Extension[] = [
 	}),
 	sessionOrchestratorExt,
 	transportHttpExt,
+	// Surface extensions — dependency order: surface-registry first, then consumers.
+	createSurfaceRegistryExtension(),
+	createTransportWsExtension(),
+	createLoadedExtensionsExtension(),
 ];
 
 async function boot(): Promise<void> {
diff --git a/packages/host-bin/tsconfig.json b/packages/host-bin/tsconfig.json
index 70ff95c..3630394 100644
--- a/packages/host-bin/tsconfig.json
+++ b/packages/host-bin/tsconfig.json
@@ -5,11 +5,10 @@
 	"references": [
 		{ "path": "../kernel" },
 		{ "path": "../storage-sqlite" },
-		{ "path": "../conversation-store" },
-		{ "path": "../auth-apikey" },
-		{ "path": "../credential-store" },
-		{ "path": "../provider-openai-compat" },
-		{ "path": "../session-orchestrator" },
-		{ "path": "../transport-http" }
+		{ "path": "../surface-loaded-extensions" },
+		{ "path": "../surface-registry" },
+		{ "path": "../tool-read-file" },
+		{ "path": "../transport-http" },
+		{ "path": "../transport-ws" }
 	]
 }