Enhance API robustness: Add model validators, view-field filtering, and test suite.

- Added validators to Person_Base, Journal_Base, Journal_Entry_Base, Address_Base, and Contact_Base to handle null values and unsafe lookups.
- Implemented 'fields_to_exclude_from_db' ClassVar in Journal models to prevent view-only fields from causing DB errors.
- Updated Contact object map to align with DB schema.
- Added comprehensive test suite in 'tests/' directory (model validation, filtering logic).
- Updated GEMINI.md with progress.

tests/verify_imports.py

@@ -0,0 +1,36 @@
+import sys
+import os
+
+# Add current directory to path
+sys.path.append(os.getcwd())
+
+print("Attempting to import app.lib_general_v3...")
+try:
+    import app.lib_general_v3
+    print("Success: app.lib_general_v3")
+except Exception as e:
+    print(f"Failed: app.lib_general_v3 - {e}")
+    import traceback
+    traceback.print_exc()
+
+print("-" * 20)
+
+print("Attempting to import app.routers.api_crud_v3...")
+try:
+    import app.routers.api_crud_v3
+    print("Success: app.routers.api_crud_v3")
+except Exception as e:
+    print(f"Failed: app.routers.api_crud_v3 - {e}")
+    import traceback
+    traceback.print_exc()
+
+print("-" * 20)
+
+print("Attempting to import app.routers.agent_bridge...")
+try:
+    import app.routers.agent_bridge
+    print("Success: app.routers.agent_bridge")
+except Exception as e:
+    print(f"Failed: app.routers.agent_bridge - {e}")
+    import traceback
+    traceback.print_exc()