Fix FTSSampleProject JSON value converter and BlogIndexer error handling

Add EF ValueConverter for FTSSampleProject.Files so List<string> correctly
round-trips with the JSON text stored in the FTS5 column. Replace
catch-and-rethrow in BlogIndexer with continue-with-warning so a single
failed blog post doesn't abort the entire indexing run.

Author: damianh

server/src/Docs.Indexer/Indexers/BlogIndexer.cs

@@ -50,8 +50,7 @@ public async Task IndexAsync()
             }
             catch (Exception ex)
             {
-                Console.WriteLine($"  Error indexing {item.Title}: {ex.Message}");
-                throw;
+                Console.WriteLine($"  Warning: Failed to index '{item.Title}': {ex.Message}");
             }
         }
 

server/src/Docs.Mcp/Database/McpDb.cs

@@ -1,7 +1,9 @@
 // Copyright (c) Duende Software. All rights reserved.
 // See LICENSE in the project root for license information.
 
+using System.Text.Json;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
 
 namespace Docs.Mcp.Database;
 
@@ -61,6 +63,15 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
         // but we still need to configure the entities for querying
         modelBuilder.Entity<FTSDocsArticle>().HasNoKey();
         modelBuilder.Entity<FTSBlogArticle>().HasNoKey();
-        modelBuilder.Entity<FTSSampleProject>().HasNoKey();
+        modelBuilder.Entity<FTSSampleProject>(entity =>
+        {
+            entity.HasNoKey();
+
+            // FTS5 stores Files as a JSON text column — convert to/from List<string>
+            entity.Property(e => e.Files).HasConversion(
+                new ValueConverter<List<string>, string>(
+                    v => JsonSerializer.Serialize(v, JsonSerializerOptions.Default),
+                    v => JsonSerializer.Deserialize<List<string>>(v, JsonSerializerOptions.Default) ?? new List<string>()));
+        });
     }
 }