Make model required on Text2VecDigitalOcean factory

The server requires `model` (e.g. `qwen3-embedding-0.6b`); the
factory should require it too rather than silently sending a payload
the server will reject.

- `VectorizerFactory.Text2VecDigitalOcean(string model, string? baseURL = null, bool? vectorizeCollectionName = null)`
  — `model` is now required and reordered to the first position,
  since C# requires non-default params before default params.
- `PublicAPI.Unshipped.txt` updated to reflect the new signature
  (`string! model` first).
- `Test_Text2VecDigitalOcean_Omits_Unset_Optionals` renamed to
  `Test_Text2VecDigitalOcean_Omits_Unset_BaseURL`. It now passes
  `model` and only asserts that `baseURL` is omitted when unset.
  The old "model is also omitted when unset" assertion was
  inconsistent with the spec (`model` is required by the server)
  and would no longer be reachable through the factory anyway.

The `Text2VecDigitalOcean` record's `Model` property remains
nullable at the type level (matching the `Text2VecMistral` record);
required-ness is enforced at the factory entry point, which is the
documented user-facing API.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: mpartipilo

src/Weaviate.Client.Tests/Unit/TestVectorizers.cs

@@ -431,8 +431,8 @@ public void Test_Text2VecDigitalOcean_Serializes_BaseURL_And_Model()
             "default",
             v =>
                 v.Text2VecDigitalOcean(
-                    baseURL: "https://inference.do-ai.run",
                     model: "qwen3-embedding-0.6b",
+                    baseURL: "https://inference.do-ai.run",
                     vectorizeCollectionName: false
                 )
         );
@@ -457,18 +457,22 @@ public void Test_Text2VecDigitalOcean_Serializes_BaseURL_And_Model()
 
     /// <summary>
     /// Tests that Text2VecDigitalOcean omits unset optional fields so the server can apply
-    /// its defaults (no <c>baseURL</c>, no <c>model</c>).
+    /// its defaults (no <c>baseURL</c>). <c>model</c> is required by the factory so it is
+    /// always present.
     /// </summary>
     [Fact]
     [System.Diagnostics.CodeAnalysis.SuppressMessage(
         "Performance",
         "CA1869:Cache and reuse 'JsonSerializerOptions' instances",
         Justification = "<Pending>"
     )]
-    public void Test_Text2VecDigitalOcean_Omits_Unset_Optionals()
+    public void Test_Text2VecDigitalOcean_Omits_Unset_BaseURL()
     {
         // Arrange
-        var vc = Configure.Vector("default", v => v.Text2VecDigitalOcean());
+        var vc = Configure.Vector(
+            "default",
+            v => v.Text2VecDigitalOcean(model: "qwen3-embedding-0.6b")
+        );
 
         // Act
         var dto = vc.Vectorizer?.ToDto() ?? default;
@@ -489,7 +493,7 @@ public void Test_Text2VecDigitalOcean_Omits_Unset_Optionals()
 
         // Assert
         Assert.Contains("\"text2vec-digitalocean\"", json);
+        Assert.Contains("\"model\":\"qwen3-embedding-0.6b\"", json);
         Assert.DoesNotContain("\"baseURL\"", json);
-        Assert.DoesNotContain("\"model\"", json);
     }
 }

src/Weaviate.Client/Configure/VectorizerFactory.cs

@@ -755,13 +755,13 @@ public VectorizerConfig Text2VecMistral(
     /// See the <a href="https://weaviate.io/developers/weaviate/model-providers/digitalocean/embeddings">documentation</a>
     /// for detailed usage.
     /// </summary>
-    /// <param name="baseURL">The base URL where API requests should go. Defaults to <c>null</c>, which uses the server-defined default of <c>https://inference.do-ai.run</c>.</param>
     /// <param name="model">The model to use, e.g. <c>qwen3-embedding-0.6b</c>. Required by the server.</param>
+    /// <param name="baseURL">The base URL where API requests should go. Defaults to <c>null</c>, which uses the server-defined default of <c>https://inference.do-ai.run</c>.</param>
     /// <param name="vectorizeCollectionName">Whether to vectorize the collection name.</param>
     /// <returns>The vectorizer config</returns>
     public VectorizerConfig Text2VecDigitalOcean(
+        string model,
         string? baseURL = null,
-        string? model = null,
         bool? vectorizeCollectionName = null
     ) =>
         new Text2VecDigitalOcean

src/Weaviate.Client/PublicAPI.Unshipped.txt

@@ -17,4 +17,4 @@ Weaviate.Client.Models.Vectorizer.Text2VecDigitalOcean.Model.set -> void
 Weaviate.Client.Models.Vectorizer.Text2VecDigitalOcean.Text2VecDigitalOcean(Weaviate.Client.Models.Vectorizer.Text2VecDigitalOcean! original) -> void
 Weaviate.Client.Models.Vectorizer.Text2VecDigitalOcean.VectorizeCollectionName.get -> bool?
 Weaviate.Client.Models.Vectorizer.Text2VecDigitalOcean.VectorizeCollectionName.set -> void
-Weaviate.Client.VectorizerFactory.Text2VecDigitalOcean(string? baseURL = null, string? model = null, bool? vectorizeCollectionName = null) -> Weaviate.Client.Models.VectorizerConfig!
+Weaviate.Client.VectorizerFactory.Text2VecDigitalOcean(string! model, string? baseURL = null, bool? vectorizeCollectionName = null) -> Weaviate.Client.Models.VectorizerConfig!