fix: address PR review feedback (round 8)

- Fix inconsistent error code in set_collective_emoji (400 → -32603)
- Allow clearing emoji via set_collective_emoji(emoji=None)
- Remove destructiveHint from trash operations (soft deletes are recoverable)
- Change delete_collective to idempotentHint=False (requires trash precondition)
- Add restore_collective and get_trashed_collectives tools
- Add unit tests for ValueError guard, clear-emoji path, and new tools
- Add integration test for full trash/restore/delete lifecycle
- Verify move_page returns new title in response message

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

nextcloud_mcp_server/models/collectives.py

@@ -140,6 +140,13 @@ class ListTrashedPagesResponse(ListPagesResponse):
     )
 
 
+class ListTrashedCollectivesResponse(BaseResponse):
+    """Response for listing trashed collectives."""
+
+    collectives: list[Collective] = Field(description="List of trashed collectives")
+    total: int = Field(description="Total number of trashed collectives")
+
+
 class ListTagsResponse(BaseResponse):
     """Response for listing tags in a collective."""