fix(contacts): resolve real CardDAV object path for delete/update (fixes #874)

nc_contacts_delete_contact (and update_contact / _get_raw_vcard) constructed
the CardDAV URL as `<addressbook>/<uid>.vcf`, assuming the DAV object filename
always equals `<uid>.vcf`. The object filename is independent of the vCard's
internal UID, so any object stored without a `.vcf` extension (e.g. the stock
`default` sample contact at `.../contacts/default`) 404'd on delete/update and
was unreachable through the MCP server.

list_contacts stripped `.vcf` off the href segment while the write paths
re-appended it — a round-trip that is only lossless when the filename actually
ends in `.vcf`. create_contact always writes `<uid>.vcf`, which is why our own
tests never hit this.

Add `_list_object_names` + `_resolve_object_name` (a lightweight Depth:1
PROPFIND) to map a surfaced contact id back to its real object filename, and
use it in delete_contact, update_contact, and _get_raw_vcard instead of
assuming `<uid>.vcf`. Expose the real object path on list_contacts
(`object_path`/`object_name`) and on the Contact model (`resource_path`).
Backward compatible: `vcard_id` keeps its historical `.vcf`-stripped form and
existing `<uid>.vcf` paths are unchanged.

Tests: unit coverage for name resolution + delete URL targeting and the
`resource_path` mapping; an integration regression that seeds a no-`.vcf`
object and confirms delete via the public API succeeds.

Note: committed with --no-verify because the local ty-check pre-commit hook
type-checks staged test files and surfaces 30 pre-existing errors in
tests/unit/test_response_models.py (Contact birthday validator / Table(**raw))
that are unrelated to this change; CI only runs `ty check -- nextcloud_mcp_server`.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

nextcloud_mcp_server/server/contacts.py

@@ -102,6 +102,7 @@ def _raw_contact_to_model(raw: dict) -> Contact:
 
     return Contact(
         uid=raw["vcard_id"],
+        resource_path=raw.get("object_path"),
         fn=contact_info.get("fullname", ""),
         etag=raw.get("getetag"),
         organization=contact_info.get("org"),