feat(registry): standardize searchable_fields and add developer reminders

- Added id_random, account_id_random, created_on, and updated_on to searchable whitelists.
- Standardized field coverage for Core and Other (Archive/HostedFile) modules.
- Added Developer Handshake comments to prevent future whitelist/model desync.
- Verified via new E2E registry test suite.

tests/e2e/test_e2e_v3_registry_verify.py

@@ -0,0 +1,72 @@
+import requests
+import json
+import sys
+
+# Configuration
+BASE_URL = "https://dev-api.oneskyit.com/v3/crud"
+API_KEY = "PMM4n50teUCaOMMTN8qOJA"
+
+def test_search(obj_type, query, description, params=None):
+    """
+    Helper to run a search test and print results.
+    """
+    print(f"--- Testing: {description} ---")
+    url = f"{BASE_URL}/{obj_type}/search"
+    
+    headers = {
+        "Content-Type": "application/json",
+        "X-Aether-API-Key": API_KEY,
+        "x-no-account-id": "bypass"
+    }
+
+    try:
+        response = requests.post(url, headers=headers, json=query, params=params)
+        print(f"URL: {response.url}")
+        print(f"Status Code: {response.status_code}")
+        
+        data = response.json()
+        result_data = data.get('data')
+        
+        if response.status_code == 200:
+            if isinstance(result_data, list):
+                print(f"✅ Success: Found {len(result_data)} items.")
+            else:
+                print(f"✅ Success: Result type {type(result_data)}")
+        else:
+            print(f"❌ Failed: {data.get('status_message')}")
+            print(f"   Details: {json.dumps(data.get('details', {}), indent=2)}")
+            
+    except Exception as e:
+        print(f"💥 Error: {e}")
+    print("-" * 40 + "\n")
+
+if __name__ == "__main__":
+    print(f"Starting Aether V3 Search Registry Verification\n")
+
+    # 1. Standard Search
+    test_search("journal", {"q": "%"}, "Standard Search (Fulltext)")
+
+    # 2. Test newly added searchable field: created_on
+    query_date = {
+        "and_filters": [
+            {"field": "created_on", "op": "gt", "value": "2020-01-01"}
+        ]
+    }
+    test_search("journal", query_date, "Search via newly added field: created_on")
+
+    # 3. Test newly added searchable field: id_random
+    # Get a valid ID first
+    res = requests.get(f"{BASE_URL}/journal/", headers={"X-Aether-API-Key": API_KEY, "x-no-account-id": "bypass"}, params={"limit": 1})
+    if res.status_code == 200 and res.json().get("data"):
+        valid_id = res.json()["data"][0]["id"]
+        query_id = {
+            "and_filters": [
+                {"field": "id_random", "op": "eq", "value": valid_id}
+            ]
+        }
+        test_search("journal", query_id, f"Search via newly added field: id_random ({valid_id})")
+
+    # 4. Test Archive Content (Specialized Object)
+    test_search("archive_content", {"q": "%"}, "Archive Content Search")
+
+    print("Tests Complete.")