Support Model Designation By Target (#1501)

* add model targets designation

* add readme update

* update schema

* Update hub-config/model-metadata-schema.json

* Apply suggestions from code review

---------

Co-authored-by: Subekshya Bidari <37636707+sbidari@users.noreply.github.com>

Author: O957

hub-config/model-metadata-schema.json

@@ -80,9 +80,20 @@
       ]
     },
     "designated_model": {
-      "description": "Team-specified indicator for whether the model should be eligible for inclusion in a Hub ensemble and public visualization. A team may designate up to two models.",
+      "description": "Team-specified indicator for whether the model should be eligible for inclusion in a Hub ensemble and public visualization. A team may designate up to two models. Designation applies to every target the model submits unless narrowed by 'designated_targets'.",
       "type": "boolean"
     },
+    "designated_targets": {
+      "description": "Optional list of target names for which this model is designated. When present, 'designated_model=true' applies only to listed targets. When absent or empty, a designated model is eligible for every target it submits. Has no effect when 'designated_model' is false.",
+      "type": "array",
+      "items": {
+        "type": "string",
+        "enum": [
+          "wk inc covid hosp",
+          "wk inc covid prop ed visits"
+        ]
+      }
+    },
     "citation": {
       "description": "One or more citations for this model",
       "type": "string",

model-metadata/README.md

@@ -68,6 +68,8 @@ One of the following [accepted licenses](https://github.com/CDCgov/covid19-forec
 
 A team-specified boolean indicator (`true` or `false`) for whether the model should be considered eligible for inclusion in Hub ensembles and public visualizations. A team may specify up to two models as `designated_model`s for inclusion. Models which have a designated_model value of `false` will still be included in internal forecasting Hub evaluations, but not in published ensembles and visualizations.
 
+Designation applies to every target the model submits unless narrowed by the optional `designated_targets` field (see [Optional fields](#optional-fields)).
+
 ### `data_inputs`
 
 List or description of the data sources used to inform the model, in particular any dataset used that are not the [target datasets](../README.md#target-data-source) of epiweekly incident COVID-19 hospital admissions reported to NHSN or epiweekly incident emergency department visits due to COVID-19 reported to NSSP.
@@ -95,8 +97,23 @@ A boolean value (`true` or `false`) that indicates whether a model is an ensembl
 The url of a website with additional information about your model, such as detailed methods, visualizations, or interactive dashboards.
 
 ## Optional fields
+
 The following metadata fields are optional, but encouraged.
 
+### `designated_targets`
+
+A list of target names for which the model is designated. When present, narrows the effect of `designated_model: true` to only the listed targets. When absent or empty, a designated model is eligible for every target it submits. Has no effect when `designated_model` is `false`. Example:
+
+```
+designated_targets: ["wk inc covid hosp"]
+```
+
+or for multiple targets:
+
+```
+designated_targets: ["wk inc covid hosp", "wk inc covid prop ed visits"]
+```
+
 ### `model_version`
 An identifier of the version of the model. We recommend [semantic versioning](https://semver.org/) style: `X.Y` or `X.Y.Z`, so `1.2` for version 1.2.