add examples for default model setting and note precedence of preferred model over default model

Author: sharon-wang

extensions/positron-assistant/package.json

@@ -322,7 +322,12 @@
             "additionalProperties": {
               "type": "string"
             },
-            "markdownDescription": "%configuration.defaultModels.description%"
+            "markdownDescription": "%configuration.defaultModels.description%",
+            "examples": [
+              {
+                "anthropic-api": "Claude Sonnet 4.5"
+              }
+            ]
           }
         }
       }

extensions/positron-assistant/package.nls.json

@@ -36,7 +36,6 @@
 	"configuration.providerTimeout.description": "Specifies the timeout in seconds when signing in to a provider.",
 	"configuration.alwaysIncludeCopilotTools.description": "Allow any model in Positron Assistant to use tools provided by GitHub Copilot.\n\nThis requires that you are signed into Copilot, and **may send data to Copilot models regardless of the selected provider**.\n\nSee also: `#chat.useCopilotParticipantsWithOtherProviders#`",
 	"configuration.filterModels.description": "A list of [glob patterns](https://aka.ms/vscode-glob-patterns) to filter available LLM models in Positron Assistant.\n\nAllows only language models with ID or name matching at least one of the patterns to be used. Defaults to allowing all models.\n\nRequires a restart to take effect.\n\nExamples:\n- `Claude*` allows all models starting with 'Claude'\n- `GPT-5` allows models named 'GPT-5'\n- `**/google/gemini-*` allows all models with '/google/gemini-' in the ID",
-	"configuration.preferredModel.description": "A preferred model ID or name (partial match supported) to use if available in Positron Assistant.\n\nRequires a restart to take effect.\n\nExamples:\n- `Claude Sonnet 4.5` prefers the model named 'Claude Sonnet 4.5'\n- `GPT-5` prefers the model named 'GPT-5'",
-	"configuration.defaultModels.description": "A mapping of provider IDs to default model IDs or names (partial match supported) to use for that provider in Positron Assistant."
-
+	"configuration.preferredModel.description": "A preferred model ID or name (partial match supported) to use if available in Positron Assistant for the current provider.\n\nTakes precedence over `#positron.assistant.defaultModels#`.\n\nRequires a restart to take effect.\n\nExamples:\n- `Claude Sonnet 4.5` prefers the model named 'Claude Sonnet 4.5'\n- `GPT-5` prefers the model named 'GPT-5'",
+	"configuration.defaultModels.description": "A mapping of provider IDs to default model IDs or names (partial match supported) to use for that provider in Positron Assistant.\n\n`#positron.assistant.preferredModel#` takes precedence over this setting.\n\nRequires a restart to take effect.\n\nExample: Item `anthropic-api` and Value `Claude Sonnet 4.5` sets the default model for Anthropic to 'Claude Sonnet 4.5'"
 }