feat(agent-loop): add antigravity block and interface metadata to Antigravity manifest

- Populate antigravity capabilities and interface block in agent-loop/.antigravity-plugin/plugin.json
- Update scripts/validate-plugins.sh to validate interface and mode objects for Antigravity mode

Co-Authored-By: duyetbot <duyetbot@users.noreply.github.com>

Author: duyet

agent-loop/.antigravity-plugin/plugin.json

@@ -5,5 +5,28 @@
   "author": { "name": "duyetbot" },
   "license": "MIT",
   "skills": "./skills/",
-  "commands": "./commands/"
+  "commands": "./commands/",
+  "antigravity": {
+    "skills": [
+      "agent-loop-orchestrator",
+      "agent-loop-triage",
+      "agent-loop-autoreview",
+      "agent-loop-browser"
+    ],
+    "commands": [
+      "agent-loop:start",
+      "agent-loop:stop",
+      "agent-loop:status",
+      "agent-loop:triage",
+      "agent-loop:autoreview",
+      "agent-loop:resume"
+    ]
+  },
+  "interface": {
+    "displayName": "Agent Loop",
+    "shortDescription": "Continuous overnight/day repo maintenance with autonomous agent loops. Triage, autoreview, browser automation, and parallel agent work.",
+    "developerName": "duyetbot",
+    "category": "Automation",
+    "capabilities": ["Skill", "Command"]
+  }
 }

scripts/validate-plugins.sh

@@ -80,9 +80,11 @@ if mode in ("codex", "antigravity"):
         if not os.path.exists(target):
             errors.append(f"'{field}' path does not exist: {value}")
 
-if mode == "codex":
+if mode in ("codex", "antigravity"):
     interface = data.get("interface")
-    if not isinstance(interface, dict):
+    if interface is None:
+        errors.append("missing required field: 'interface'")
+    elif not isinstance(interface, dict):
         errors.append("'interface' must be an object")
     else:
         for field in ("displayName", "shortDescription", "developerName", "category"):
@@ -93,6 +95,17 @@ if mode == "codex":
             if not isinstance(capabilities, list) or not all(isinstance(item, str) and item.strip() for item in capabilities):
                 errors.append("'interface.capabilities' must be an array of non-empty strings")
 
+    mode_obj = data.get(mode)
+    if mode_obj is not None:
+        if not isinstance(mode_obj, dict):
+            errors.append(f"'{mode}' must be an object")
+        else:
+            for field in ("skills", "commands"):
+                val = mode_obj.get(field)
+                if val is not None:
+                    if not isinstance(val, list) or not all(isinstance(item, str) and item.strip() for item in val):
+                        errors.append(f"'{mode}.{field}' must be an array of non-empty strings")
+
 if errors:
     for error in errors:
         print(f"  - {error}", file=sys.stderr)