feat: Fabric channel plugin for OpenClaw (Phase 1, B1)

OpenClaw channel plugin: defineChannelPluginEntry + createChatChannelPlugin.
Inbound via channel-turn kernel (wakeup -> admission: true=dispatch,
else drop+recordHistory). One Fabric socket per agent identity in the
plugin runtime (no sidecar). Center API-key agent auth. Tools:
fabric-register, create-{chat,work,report,discussion}-channel,
discussion-complete (post summary + close channel).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

openclaw.plugin.json

@@ -0,0 +1,51 @@
+{
+  "id": "fabric",
+  "kind": "channel",
+  "channels": ["fabric"],
+  "name": "Fabric",
+  "description": "Fabric channel plugin — OpenClaw agents speak in Fabric guilds",
+  "activation": {
+    "onStartup": true
+  },
+  "contracts": {
+    "tools": [
+      "fabric-register",
+      "create-chat-channel",
+      "create-work-channel",
+      "create-report-channel",
+      "create-discussion-channel",
+      "discussion-complete"
+    ]
+  },
+  "configSchema": {
+    "type": "object",
+    "additionalProperties": false,
+    "properties": {
+      "identityFilePath": {
+        "type": "string",
+        "description": "Path to the agent identity registry JSON (agentId -> Fabric API key). Default ~/.openclaw/fabric-identity.json"
+      },
+      "debugMode": { "type": "boolean", "default": false }
+    },
+    "required": []
+  },
+  "channelConfigs": {
+    "fabric": {
+      "schema": {
+        "type": "object",
+        "additionalProperties": false,
+        "properties": {
+          "centerApiBase": {
+            "type": "string",
+            "description": "Fabric Center API base, e.g. http://localhost:7001/api"
+          },
+          "dmSecurity": { "type": "string" },
+          "allowFrom": { "type": "array", "items": { "type": "string" } }
+        }
+      },
+      "uiHints": {
+        "centerApiBase": { "label": "Center API base" }
+      }
+    }
+  }
+}