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.

opencode.json

@@ -1,12 +1,25 @@
 {
   "$schema": "https://opencode.ai/config.json",
   "default_agent": "instruction",
+  "websearch": {
+    "provider": "exa"
+  },
   "permissions": [
     {
       "action": "*",
       "resource": "*",
       "effect": "ask"
     },
+    {
+      "action": "browser",
+      "resource": "*",
+      "effect": "deny"
+    },
+    {
+      "action": "browser_*",
+      "resource": "*",
+      "effect": "deny"
+    },
     {
       "action": "external_directory",
       "resource": "*",
@@ -207,6 +220,11 @@
       "resource": "*",
       "effect": "allow"
     },
+    {
+      "action": "websearch",
+      "resource": "*",
+      "effect": "allow"
+    },
     {
       "action": "subagent",
       "resource": "*",
@@ -217,11 +235,6 @@
       "resource": "*",
       "effect": "allow"
     },
-    {
-      "action": "todoread",
-      "resource": "*",
-      "effect": "allow"
-    },
     {
       "action": "todowrite",
       "resource": "*",
@@ -232,21 +245,21 @@
       "resource": "*",
       "effect": "allow"
     },
-    {
-      "action": "get_operational_task_context",
-      "resource": "*",
-      "effect": "allow"
-    },
-    {
-      "action": "query_operational_task_data",
-      "resource": "*",
-      "effect": "allow"
-    },
     {
       "action": "publish_task_report",
       "resource": "*",
       "effect": "allow"
     },
+    {
+      "action": "publish_task_progress",
+      "resource": "*",
+      "effect": "allow"
+    },
+    {
+      "action": "publish_task_presentation",
+      "resource": "*",
+      "effect": "allow"
+    },
     {
       "action": "propose_task_action",
       "resource": "*",
@@ -257,11 +270,6 @@
       "resource": "*",
       "effect": "allow"
     },
-    {
-      "action": "query_project_data",
-      "resource": "*",
-      "effect": "allow"
-    },
     {
       "action": "final_answer",
       "resource": "*",
@@ -292,16 +300,6 @@
       "resource": "*",
       "effect": "allow"
     },
-    {
-      "action": "web_search",
-      "resource": "*",
-      "effect": "allow"
-    },
-    {
-      "action": "geocode",
-      "resource": "*",
-      "effect": "allow"
-    },
     {
       "action": "mcp_*",
       "resource": "*",