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.

scripts/start-isolated-integration.ts

@@ -28,9 +28,10 @@ await mkdir(dataRoot, { recursive: true });
 const sharedEnvironment = {
   ...process.env,
   AGENT_INTERNAL_TOKEN: bridgeToken,
-  CONVERSATION_WORKSPACE_ROOT: join(dataRoot, "conversation-workspaces"),
-  TJWATER_AGENT_WORKSPACE_ROOT: join(dataRoot, "conversation-workspaces"),
+  CONVERSATION_WORKSPACE_ROOT: join(dataRoot, "session-workspaces"),
+  TJWATER_AGENT_WORKSPACE_ROOT: join(dataRoot, "session-workspaces"),
   TJWATER_AGENT_INTERNAL_BASE_URL: agentBaseUrl,
+  TJWATER_AGENT_MCP_CONNECTION_PATH: join(dataRoot, "mcp-query", "connection.json"),
   // Retained for tools loaded by an older compatible OpenCode process.
   TJWATER_AGENT_INTERNAL_TOKEN: bridgeToken,
 };
@@ -40,11 +41,12 @@ const opencode = await startOpencode2({
   hostname: "127.0.0.1",
   port: opencodePort,
   timeout: 30_000,
-  config: serviceOpencodeConfig(JSON.parse(await readFile(join(projectRoot, "opencode.json"), "utf8"))),
+  config: serviceOpencodeConfig(JSON.parse(await readFile(join(projectRoot, "opencode.json"), "utf8")), undefined, sharedEnvironment.CONVERSATION_WORKSPACE_ROOT),
   env: {
     ...sharedEnvironment,
     XDG_CACHE_HOME: join(dataRoot, "xdg-cache"),
     XDG_DATA_HOME: join(dataRoot, "xdg-data"),
+    OPENCODE_DB: join(dataRoot, "xdg-data", "opencode", "opencode.db"),
     XDG_STATE_HOME: join(dataRoot, "xdg-state"),
   },
 });
@@ -81,7 +83,6 @@ try {
       MEMORY_STORAGE_DIR: join(dataRoot, "memory"),
       OPENCODE_SKILLS_ROOT_DIR: join(dataRoot, "skills"),
       PERSISTENCE_BACKUP_DIR: join(dataRoot, "backup"),
-      RESULT_REF_STORAGE_DIR: join(dataRoot, "result-refs"),
       SESSION_LEARNING_STATE_STORAGE_DIR: join(dataRoot, "session-learning-state"),
       SESSION_METADATA_STORAGE_DIR: join(dataRoot, "session-metadata"),
       SESSION_TRANSCRIPT_STORAGE_DIR: join(dataRoot, "session-transcripts"),