feat(agent): unify MCP tools and adopt Responses delivery

Move project and host queries into native MCP with host-owned OAuth/context,
while retaining memory, skills, actions and publication plugins. Add nearby-model
queries and explicit chat/task/learning model defaults.

Adopt Responses HTTP/SSE and native steer/queue inbox delivery, preserving scoped
session ownership, pending input edits and investigation communication.

Disable local-provider discovery: Server /health allowed native vLLM to probe
/v1/models on port 8000. A native before/after regression prevents recurrence.

Validation: 170 focused Bun tests; service/plugin typechecks; native discovery,
provider-discovery and input-inbox smoke checks; no paid model inference.

src/routes/chatUiState.ts

@@ -1,4 +1,5 @@
 import { type PermissionReply } from "../runtime/opencode.js";
+import type { ResponseInputTracker } from "../chat/response-inputs.js";
 import type { UIEnvelopePayload } from "../uiEnvelope/types.js";
 import {
   type PermissionRequestPayload,
@@ -14,6 +15,7 @@ export type StreamSubscriber = {
 };
 
 export type ActiveRun = {
+  inputs?: ResponseInputTracker;
   clientSessionId: string;
   controller: AbortController;
   messages: unknown[];