docs: replace stale claude-sonnet-4-5 with 4-6, normalize Node version, remove stale dates

docs/concepts/architecture.md

@@ -7,8 +7,6 @@ title: "Gateway Architecture"
 
 # Gateway architecture
 
-Last updated: 2026-01-22
-
 ## Overview
 
 - A single long‑lived **Gateway** owns all messaging surfaces (WhatsApp via

docs/concepts/compaction.md

@@ -31,7 +31,7 @@ You can optionally specify a different model for compaction summarization via `a
   "agents": {
     "defaults": {
       "compaction": {
-        "model": "openrouter/anthropic/claude-sonnet-4-5"
+        "model": "openrouter/anthropic/claude-sonnet-4-6"
       }
     }
   }

docs/concepts/model-providers.md

@@ -255,7 +255,7 @@ See [/providers/kilocode](/providers/kilocode) for setup details.
 ### Other bundled provider plugins
 
 - OpenRouter: `openrouter` (`OPENROUTER_API_KEY`)
-- Example model: `openrouter/anthropic/claude-sonnet-4-5`
+- Example model: `openrouter/anthropic/claude-sonnet-4-6`
 - Kilo Gateway: `kilocode` (`KILOCODE_API_KEY`)
 - Example model: `kilocode/anthropic/claude-opus-4.6`
 - MiniMax: `minimax` (`MINIMAX_API_KEY`)

docs/concepts/multi-agent.md

@@ -388,7 +388,7 @@ Split by channel: route WhatsApp to a fast everyday agent and Telegram to an Opu
         id: "chat",
         name: "Everyday",
         workspace: "~/.openclaw/workspace-chat",
-        model: "anthropic/claude-sonnet-4-5",
+        model: "anthropic/claude-sonnet-4-6",
       },
       {
         id: "opus",
@@ -422,7 +422,7 @@ Keep WhatsApp on the fast agent, but route one DM to Opus:
         id: "chat",
         name: "Everyday",
         workspace: "~/.openclaw/workspace-chat",
-        model: "anthropic/claude-sonnet-4-5",
+        model: "anthropic/claude-sonnet-4-6",
       },
       {
         id: "opus",
@@ -501,7 +501,7 @@ Notes:
 
 ## Per-Agent Sandbox and Tool Configuration
 
-Starting with v2026.1.6, each agent can have its own sandbox and tool restrictions:
+Each agent can have its own sandbox and tool restrictions:
 
 ```js
 {