fix(agent): report phone numbers from resolve_contact when a matched contact has no email (#4327)

When a CardDAV contact matched the search query but had no email
address (only phone numbers), the tool silently dropped it and
returned 'No contacts found'.  Fall back to the contact's phone
number(s) so the caller still receives usable information.

Refs: #4178 (the contacts-domain classifier fix that made the model
actually call resolve_contact for contacts queries, surfacing this
pre-existing gap)

src/tool_schemas.py

@@ -1009,7 +1009,7 @@ FUNCTION_TOOL_SCHEMAS = [
         "type": "function",
         "function": {
             "name": "resolve_contact",
-            "description": "Look up a contact's email address by name. Searches CardDAV address book and sent email history. Use when the user says 'message [name]' or 'email [name]' without an email address.",
+            "description": "Look up a contact by name. Searches CardDAV address book and sent email history. Returns email addresses (when available) or phone numbers. Use when the user says 'message [name]', 'email [name]', or asks for someone's contact details.",
             "parameters": {
                 "type": "object",
                 "properties": {